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Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by numpy-thagoras on Tuesday January 07, 2025 @02:19PM (#42626198)
Similar CUDA core counts for most SKUs compared to last gen (except in the 5090 vs. 4090 comparison). Similar clock speeds compared to the 40-series.

The 5090 just has way more CUDA cores and uses proportionally more power compared to the 4090, when going by CUDA core comparisons and clock speed alone.

All of the "massive gains" were comparing DLSS and other optimization strategies to standard hardware rendering.

Something tells me Nvidia made next to no gains for this generation.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by danudey on Tuesday January 07, 2025 @03:58PM (#42627371)
> All of the "massive gains" were comparing DLSS and other optimization strategies to standard hardware rendering.

> Something tells me Nvidia made next to no gains for this generation.

Sounds to me like they made "massive gains". In the end, what matters to gamers is

1. Do my games look good? 2. Do my games run well?

If I can go from 45 FPS to 120 FPS and the quality is still there, I don't care if it's because of frame generation and neural upscaling and so on. I'm not going to be upset that it's not lovingly rasterized pixel by pixel if I'm getting the same results (or better, in some cases) from DLSS.

To say that Nvidia made no gains this generation makes no sense when they've apparently figured out how to deliver better results to users for less money.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by bitmasher9 on Tuesday January 07, 2025 @04:18PM (#42627622)
Rasterizing results in better graphics quality than DLSS if compute is not a limiting factor. They are trying to do an apples to oranges comparison by comparing the FPS of standard rendering to upscaled images.

I use DLSS type tech, but you lose a lot of fine details with it. Far away text looks blurry, textures aren’t as rich, and lines between individual models lose their sharpness.

Also, if you’re spending $2000 for a toy you are allowed to have high standards.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by unusualmonkey on Tuesday January 07, 2025 @06:39PM (#42629079)
> Rasterizing results in better graphics quality than DLSS if compute is not a limiting factor.

Sure, but compute is a limiting factor.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by bitmasher9 on Wednesday January 08, 2025 @12:14PM (#42636275)
I was demonstrating the Apples to Oranges comparison. If they were both free no one would pick DLSS. It shows Rasterizing is preferable. So comparing Rasterizing performance to DLSS performance is dishonest.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by unusualmonkey on Wednesday January 08, 2025 @10:11PM (#42641218)
Except that if rendering was magically free... why not just pathtrace everything?

DLSS might not be as good as pure unlimited pathtracing, but for a given budget it might be better than rasterization alone.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by bitmasher9 on Thursday January 09, 2025 @11:39AM (#42647344)
I agree it’s worth the trade off. I use upscalers a lot.

I’m saying that it’s different enough that you shouldn’t compare the two.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by maxglute on Tuesday January 07, 2025 @05:27PM (#42628432)
> if compute is not a limiting factor.

If we're moving towards real time tracing compute is going to always be a limitting factor, as it was in the days of pre rendering. Granted currently raster techniques can simulate ray trace pretty well in many scenarios and looks much better in motion, IMO that's more limitation of real time ray trace. There's a bunch of image quality improvements beyond raster to be gained if enough compute is throw at ray tracing, i think a lot of dlss / frame generation goal is basically to offload more cpu to generate higher IQ hero frames while filling in blanks.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @04:39PM (#42627898)
DLSS 4 uses a completely new model with twice as many parameters and seems to be a big improvement.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by bitmasher9 on Tuesday January 07, 2025 @04:56PM (#42628108)
I hope so, because it looks like 8k traditional rendering won’t be an option for this decade.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by xbar on Tuesday January 07, 2025 @07:43PM (#42629598)
Will NEXT decade be possible?

8k traditional rendering at 144Hz is a lot of pixels. We are seeing a 25%/3 years improvement cycle on traditional rendering at this point, and we need about 8x improvement in current performance to get there.

2040 is definitely possible, but certainly not guaranteed.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by bitmasher9 on Wednesday January 08, 2025 @12:16PM (#42636304)
So at 2040 we might be able to render at top 2025 display specs.

Makes you wonder how far ahead displays will be in 2040. I can imagine display prices falling in price and increasing in quality to the point where many homes just have displays paneled around the walls instead of paint.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by kridsdale3 on Wednesday January 08, 2025 @02:08PM (#42637389)
You won't be using display panels / monitors at all. It will be the Apple Vision Pro 14 Pro Max. A tiny thing you touch on your head and you view the rasterized world at 12k 120fps all around you.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by AdrianB1 on Tuesday January 07, 2025 @08:06PM (#42629754)
Even 4k monitors are relatively rare and most monitors today are still 1080p, 60 Hz. Yes, you don't need a 5090 to play games on that, but 5090 is a very niche product, while x060 cards are the overwhelming majority. 8k rendering is needed just for the 5 or 6 people that wants it.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @06:02PM (#42628767)
there aren't many 8k monitors. I would rather have 300fps 4k
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Teever on Tuesday January 07, 2025 @08:11PM (#42629786)
What is the draw to 300fps?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Filligree on Tuesday January 07, 2025 @09:03PM (#42630125)
VR, probably.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @11:20PM (#42630871)
People with 240Hz or higher monitors. 4K is enough for spatial resolution then it is better to increase temporal resolution. 4K at 240Hz or higher looks like a window.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @11:26PM (#42630899)
240Hz or higher monitors. 4K is enough for spatial resolution then it is better to increase temporal resolution. 4K at 240Hz stops looking like looking at a screen and starts looking out a window.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by delamon on Wednesday January 08, 2025 @08:01AM (#42633725)
4K alone is not enough to define spatial resolution. You also need take into account physical dimensions. DPI is a better way to describe spatial resolution. Anything better than 200 DPI is good, better than 300 is awesome.

Unfortunately, there are no 4K displays with 200+ DPI on the market. If you want high DPI you either need pick glossy 5k@27" or go to 6k/8k.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Wednesday January 08, 2025 @12:55PM (#42636689)
of course "normal viewing distances" is always implied when talking about monitors. And if you REALLY want to get pedantic you need to talk about pixels per degree. The human eye can see about 60. according to the very handy site https://qasimk.io/screen-ppd/

a 27" 1080p screen has 37ppd at 2 feet.

a 42" 4k screen has 51ppd at 2 feet.

a 27" 8k screen has 147ppd at 2 feet which is just absurd.

You have to get to 6 inches for the PPD to be 61

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by numpy-thagoras on Wednesday January 08, 2025 @10:19PM (#42641267)
But a 42" 8K screen should have around ~100 ppd, which is really nice but not unnecessarily detailed.

I know I'll be gunning for the 42" 8K's whenever they actually reach a decent market price. Sigh, still too many years away.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by delamon on Thursday January 09, 2025 @10:42AM (#42646715)
> The human eye can see about 60

I cannot brag with sharp eyesight, but I can definitely tell difference between 4k@27" at 60cm = 73PPD and 5k@27" at 60cm = 97PPD. Text is much crisper on the latter.

I've also compared Dell 8k to 6k. There is a still a difference, but it is not that big.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Thursday January 09, 2025 @11:59AM (#42647561)
"Much crisper"

You must have exceptional eyesight.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Andrew6rant on Wednesday January 08, 2025 @01:07PM (#42636798)
> Unfortunately, there are no 4K displays with 200+ DPI on the market.

There are 4k 24" monitors (almost 200 DPI) and 4k 18.5" portable monitors (more than 200 DPI) you can buy nowadays

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by wtallis on Wednesday January 08, 2025 @05:48PM (#42639342)
4k 24" monitors used to exist, but they've disappeared from the market and now the choices are either 27+" or laptop panels.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @07:25AM (#42665416)
Why did they stop making those? When I went to 4K, I wanted to get a 24” monitor, but there were none.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by itfossil on Wednesday January 08, 2025 @06:48AM (#42633230)
Well if they can reach 300fps at 4k then they can prove to everybody once and for all that their dick is bigger than everybody elses.

Cause it ain't about the gameplay or the usefulness. It's all about that big dick energy.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by brokenmachine on Tuesday January 07, 2025 @05:33PM (#42628488)
Why is that an issue? Do you have an 8k monitor?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by cybercity on Tuesday January 07, 2025 @10:35PM (#42630623)
DLSS is becoming the standard rendering.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by krige on Wednesday January 08, 2025 @04:22AM (#42632445)
It's not. It's becoming the standard lazy choice for devs though.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by dragontamer on Tuesday January 07, 2025 @04:09PM (#42627494)
Because if two frames are fake and only one frame is based off of real movements, then you've actually lost a fair bit of latency and will have noticably laggier controls.

Making better looking individual frames and benchmarks for worse gameplay experiences is an old tradition for these GPU makers.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by lovich on Tuesday January 07, 2025 @04:31PM (#42627802)
If anyone thinks they are having laggier controls or losing latency off of single frames I have a bridge to sell them.

A game running at 60 fps averages around ~16 ms and good human reaction times don’t go much below 200ms.

Users who “notice” individual frames are usually noticing when a single frame is lagging for the length of several frames at the average rate. They aren’t noticing anything within the span of an average frame lifetime

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by gmueckl on Tuesday January 07, 2025 @08:10PM (#42629779)
What I think is going on here has to do with lousy game engine implementations: with modern graphics APIs you have to take extra steps beyond relying on the swapchain to avoid running ahead of the GPU for multiple frames. It's not obvious and and I suspect a lot of games aren't that good at managing that. If the CPU runs ahead, you have a massive multi-frame input-to-screen lag that changes a lot with monitor FPS. But it's not the extra frames themselves that make the difference. It's just correcting for poor code.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by foxhill on Tuesday January 07, 2025 @04:41PM (#42627913)
you’re conflating reaction times and latency perception. these are not the same. humans can tell the difference down to 10ms, perhaps lower.

if you added 200ms latency to your mouse inputs, you’d throw your computer out the of the window pretty quickly.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by yzydserd on Wednesday January 08, 2025 @01:33AM (#42631606)
Or at least defenestrate the mouse.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by DanielHB on Thursday January 09, 2025 @07:52AM (#42644809)
yeah the "distance between frames" latency is just one overhead, everything adds up until you get real latency. 10ms for your wireless mouse then 3ms for your I/O hardware then 5ms for the game engine to process your input then 20ms for the graphics pipeline and so on and on.

30 FPS is 33.33333 MS 60 FPS is 16.66666 MS 90 FPS is 11.11111 MS 120 FPS is 8.333333 MS 140 FPS is 7.142857 MS 144 FPS is 6.944444 MS 180 FPS is 5.555555 MS 240 FPS is 4.166666 MS

Going from 30fps to 120fps is 25ms which is totally 100% noticeable even for layman (I actually tested this with my girlfriend, she could tell between 60fps and 120fps as well), but these generated frames from DLSS don't help with this latency _at all_.

Although the nVidia Reflex technology can help with this kind of latency in some situations in some non quantifiable ways.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by heyda on Tuesday January 07, 2025 @04:47PM (#42627981)
You think normal people can't tell? Go turn your monitor to 60hz in your video options and move your mouse in circles on your desktop, then go turn it back to 144hz or higher and move it around on your screen. If an average csgo or valorant player where to play with framegen while the real fps was about 60 and the rest of the frames where fake, it would be so completely obvious it's almost laughable. That said the 5090 can obviously run those games at 200+fps so they would just turn off any frame gen stuff. But a new/next gen twitch shooter will for sure expose it.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by samplatt on Tuesday January 07, 2025 @09:23PM (#42630210)
>If an average csgo or valorant player were to play with framegen while the real fps was about 60

That's just it isn't. This stuff isn't "only detectable by profession competitive gamers" like many are proposing. It's instantly noticeable to the average gamer.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by swinglock on Tuesday January 07, 2025 @05:47PM (#42628620)
I'll take that bridge off your hands.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by BrawnyBadger53 on Tuesday January 07, 2025 @09:34PM (#42630270)
I can and do notice when a driver update or similar switches my monitor's refresh rate or mouse polling rate down. In the game I play most there is an inbuilt framerate test tool to see what the best framerate you can notice the difference between visually is. I and many other players are consistent (20 correct in a row) up to 720fps.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @04:41PM (#42627922)
DLSS 4 can actually generate 3 frames for ever 1 raster frame. When talking about frame rates well above 200 per second a few extra frames isn't that big of a deal unless you are a professional competitive gamer.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by sempron64 on Tuesday January 07, 2025 @07:41PM (#42629583)
If you're buying a ridiculously expensive card for gaming you likely consider yourself a pro gamer. I don't think ai interpolation will be popular in the market
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @11:05PM (#42630796)
It really depends on how well it works.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by CSDude on Tuesday January 07, 2025 @04:05PM (#42627447)
I have 2070 Super. Latest Call of Duty runs on 4k with good quality using DLSS with 60 fps and I can't notice at all (unless I look very closely, even with my 6k ProDisplay XDR) so yeah I was thinking of building a 5090 based computer and it will probably last many more years than my 2070 super with latest AI developments.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by throwaway48476 on Tuesday January 07, 2025 @04:03PM (#42627419)
Fake frames, fake gains
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ThrowawayTestr on Tuesday January 07, 2025 @04:10PM (#42627520)
The human eye can't see more than 60 fps anyway
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by geerlingguy on Tuesday January 07, 2025 @04:22PM (#42627672)
Can definitely see more than 60, but it varies how much more you can see. For me it seems like diminishing returns beyond 144Hz.

Though some CRT emulation techniques require more than that to scale realistic 'flickering' effects.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by AdrianB1 on Tuesday January 07, 2025 @08:10PM (#42629783)
You are right, but diminishing returns technically start around 60.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @04:48PM (#42627992)
i can tell up to about 144Hz but struggle to really notice going from 144 to 240Hz. Even if you don't consciously notice the higher refresh rate it could still help for really fast paced games like competitive FPS if you can actually generate that many frames per second by reducing input latency and if you can actually respond fast enough.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by scotty79 on Wednesday January 08, 2025 @05:09AM (#42632704)
Same with me. At least on LCD. I'm still gonna get 480hz OLED display because I'm curious.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Salgat on Tuesday January 07, 2025 @05:36PM (#42628518)
The human eyes are analog low pass filters, so beyond 60Hz is when things start to blur together, which is still desirable since that's what we see in real life. But there is a cutoff where even the blurring itself can no longer help increase fidelity. Also keep in mind that this benefit helps visuals even when the frame rate is beyond human response time.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Sohcahtoa82 on Tuesday January 07, 2025 @06:36PM (#42629050)
This is factually incorrect and I don't know where people get this idea from.

Just moving my mouse around, I can tell the difference between 60 and 144 fps when I move my pointer from my main monitor (144 hz) to my second monitor (60 hz).

Watching text scroll is noticeably smoother and with less eye tracking motion blur at 144 hz versus 60.

An object moving across my screen at 144 fps will travel fewer pixels per frame than 60 fps. This gain in motion fluidity is noticeable.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by juped on Wednesday January 08, 2025 @03:06AM (#42632108)
I remember when it was "the human eye can't see more than cinematic 24fps" sour grapes by people who couldn't get 60fps
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by nvarsj on Wednesday January 08, 2025 @07:09AM (#42633341)
This is laughably false and easy to disprove. Blurbusters did an analysis of this many years ago and we won't get "retina" refresh rates until we're at 1000Hz.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @04:44PM (#42627951)
Are DLSS frames any more fake than the computed P or B frames?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by mdre on Tuesday January 07, 2025 @04:56PM (#42628109)
Yes.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Tuesday January 07, 2025 @06:02PM (#42628757)
how so?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by shock-value on Tuesday January 07, 2025 @07:38PM (#42629562)
P and B frames are compressed versions of a reference image. Frames resulting from DLSS frame generation are predictions of what a reference image might look like even though one does not actually exist.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by scotty79 on Wednesday January 08, 2025 @05:05AM (#42632678)
Compression and prediction are the same. Decompressing a lossy format is guessing how the original image might have looked like. The difference between fake frames and P and B frames is that the difference between prediction of fake frame and real frame is dependant on the user input.

... now I wonder ... Do DLSS models take mouse movements and keypresses into account?

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Wednesday January 08, 2025 @11:39AM (#42635929)
But MPEG is lossy compression which means they are kind of a just a guess. That is why MPEG uses motion vectors.

"MPEG uses motion vectors to efficiently compress video data by identifying and describing the movement of objects between frames, allowing the encoder to predict pixel values in the current frame based on information from previous frames, significantly reducing the amount of data needed to represent the video sequence"

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by wtallis on Wednesday January 08, 2025 @05:58PM (#42639433)
There's a real difference between a lossy approximation as done by video compression, and the "just a guess" done by DLSS frame generation. Video encoders have the real frame to use as a target; when trying to minimize the artifacts introduced by compressing with reference to other frames and using motion vectors, the encoder is capable of assessing its own accuracy. DLSS fundamentally has less information when generating new frames, and that's why it introduces much worse motion artifacts.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by UltraSane on Thursday January 09, 2025 @08:33PM (#42651606)
it would be VERY interesting to have actual quantitative data on how many possible I video frames map to a specific P or B frame vs how many possible raster frames map to a given predicted DLSS frame. The lower this ration the more "accurate" the prediction is.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by m3kw9 on Tuesday January 07, 2025 @05:31PM (#42628476)
The fps gains are directly because of the AI compute cores, I’d say that’s a net gain but not a the traditional sense preAI.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ahartmetz on Tuesday January 07, 2025 @07:36PM (#42629540)
Kind of a half gain: smoothness improved, latency same or slightly worse.

By the way, I thought these AI things served to increase resolution, not frame rate. Why doesn't it work that way?

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by throwaway48476 on Tuesday January 07, 2025 @09:52PM (#42630378)
It's both. And it's going to continue until games are 100% and AI fever dream.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ahartmetz on Thursday January 09, 2025 @02:47AM (#42642793)
Right, I should have said "generate extra pixels in every frame, not interpolate whole frames". Doing the former also increases frame rate by reducing computation per pixel.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by hervature on Tuesday January 07, 2025 @04:29PM (#42627762)
These are NVidia's financial results last quarter:

- Data Center: Third-quarter revenue was a record $30.8 billion

- Gaming and AI PC: Third-quarter Gaming revenue was $3.3 billion

If the gains are for only 10% of your customers, I would put this closer to the "next to no gains" rather than the "massive gains".

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by pshc on Tuesday January 07, 2025 @07:28PM (#42629483)
DLSS artifacts are pretty obvious to me. Modern games relying on temporal anti aliasing and raytracing tend to be blurry and flickery. I prefer last-gen games at this point, and would love a revival of “brute force” rasterization.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by AdrianB1 on Tuesday January 07, 2025 @08:09PM (#42629773)
As long as you can still disable DLSS from the game menu, it is good enough for me. I don't care about fake frames, I disable fake frames.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by everdrive on Tuesday January 07, 2025 @08:21PM (#42629854)
If you're doing frame generation you're getting input lag. Frame generation from low framerates is pretty far from ideal.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @07:47AM (#42665505)
Nvidia claims to have fixed this with Nvidia reflex 2. It will reposition the frame according to mouse movements.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Arn_Thor on Wednesday January 08, 2025 @06:46AM (#42633210)
Any frame gen gains don’t improve latency so the usefulness is reduced
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @06:58AM (#42665286)
Nvidia reflex 2 is supposed to fix that. It will recenter the frame based on mouse movements.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by nicman23 on Wednesday January 08, 2025 @01:00PM (#42636724)
>Do my games look good

i d like to point you to r/FuckTAA

>Do my games run well

if the internal logic is still in sub 120 hz and it is a twichy game, then no

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by laweijfmvo on Tuesday January 07, 2025 @05:17PM (#42628332)
I started thinking today, when Nvidia seemingly keeps just magically increasing performance every two years, that they eventually have to "intel" themselves, where they haven't made any real architectural improvements in ~10 years and just suddenly power and thermals don't scale anymore and you have six generations of turds that all perform essentially the same, right?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by leetcrew on Tuesday January 07, 2025 @07:41PM (#42629576)
it's possible, but idk why you would expect that. just to pick an arbitrary example since steve ran some recent tests, a 1080 ti is more or less equal to a 4060 in raster performance, but needs more than double the power and a much more die area to do it.

https://www.youtube.com/watch?v=ghT7G_9xyDU

we do see power requirements on the high end parts every generation, but that may be to maintain the desired SKU price points. there's clearly some major perf/watt improvements if you zoom out. idk how much is arch vs node, but they have plenty of room to dissipate more power over bigger dies if needed for the high end.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by markhahn on Wednesday January 08, 2025 @10:25AM (#42635167)
how many customers care about raster performance?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by leetcrew on Wednesday January 08, 2025 @12:14PM (#42636279)
I can’t exactly compare ray tracing performance when it didn’t exist at that time. or is this a joke about rendering games no longer being the primary use case for an nvidia gpu?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Night_Thastus on Wednesday January 08, 2025 @01:22PM (#42636939)
I do. Ray tracing, DLSS and especially frame-gen cause all sorts of weird visual artifacts. I'd rather just do without any of them.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Tuesday January 07, 2025 @05:49PM (#42628636)
Nvidia is a very innovative company. They reinvent solutions to problems while others are trying to match their old solutions. As long as they can keep doing that, they will keep improving performance. They are not solely reliant on process node shrinks for performance uplifts like Intel was.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Cumpiler69 on Wednesday January 08, 2025 @04:56AM (#42632619)
>They are not solely reliant on process node shrinks for performance uplifts like Intel was.

People who keep giving intel endless shit are probably very young and don't remember how innovative Intel was in the 90s and 00s. USB, PCI-Express, Thunderbolt, etc., all Intel inventions, plus involvement in Wifi and wireless telecom standards. They are guilty of anti competitive practices and complacency in the last years but their innovations weren't just node shrinks.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Wednesday January 08, 2025 @06:04AM (#42632969)
Those standards are plumbing to connect things to the CPU. The last major innovations that Intel had in the CPU itself were implementing CISC in RISC with programmable microcode in the Pentium and SMT in the Pentium 4. Everything else has been fairly incremental and they were reliant on their process node advantage to stay on top. There was Itanium too, but that effort was a disaster. It likely caused Intel to stop innovating and just rely on its now defunct process node advantage.

Intel’s strategy after it adopted EM64T (Intel’s NIH syndrome name for amd64) from AMD could be summarized as “increase realizable parallelism through more transistors and add more CISC instructions to do key work loads faster”. AVX512 was that strategy’s zenith and it was a disaster for them since they had to cut clock speeds when AVX-512 operations ran while AMD was able to implement them without any apparent loss in clock speed.

You might consider the more recent introduction of E cores to be an innovation, but that was a copy of ARM’s big.little concept. The motivation was not so much to save power as it was for ARM but to try to get more parallelism out of fewer transistors since their process advantage was gone and the AVX-512 fiasco had showed that they needed a new strategy to stay competitive. Unfortunately for Intel, it was not enough to keep them competitive.

Interestingly, leaks from Intel indicate that Intel had a new innovation in development called Royal Core, but Pat Gelsinger cancelled it last year before he “resigned”. The cancellation reportedly lead to Intel’s Oregon design team resigning.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by markhahn on Wednesday January 08, 2025 @10:26AM (#42635183)
e cores are more like atom - intel owes no credit to arm.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by wtallis on Wednesday January 08, 2025 @05:34PM (#42639234)
Intel's E cores are literally derived from the Atom product line. But the practice of including a heterogeneous mix of CPU core types was developed and proven and made mainstream within the ARM ecosystem before being hastily adopted by Intel as an act of desperation (dragging Microsoft along for the ride).
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Wednesday January 08, 2025 @04:16PM (#42638533)
> AVX512 was that strategy’s zenith and it was a disaster for them since they had to cut clock speeds when AVX-512 operations ran while AMD was able to implement them without any apparent loss in clock speed.

AMD up until zen 5 didn't have a full AVX-512 support so not exactly a fair comparison. Intel designs don't suffer from that issue AFAIU for couple of iterations already.

But I agree with you, I always thought and I still do that Intel has a very strong CPU core design but where AMD changed the name of the game IMHO is the LLC cache design. Hitting as much as ~twice lower LLC latency is insane. To hide this big of a difference in latency, Intel has to pack larger L2+LLC cache sizes.

Since LLC+CCX design scales so well AMD is also able to pack ~50% more cores per die, something Intel can't achieve even with the latest Granite Rapids design.

These two reasons let alone are big things for data center workloads so I really wonder how Intel is going to battle that.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Wednesday January 08, 2025 @11:04PM (#42641504)
AVX-512 is around a dozen different ISA extensions. AMD implemented the base AVX-512 and more with Zen 4. This was far more than Intel had implemented in skylake-X where their problems started. AMD added even more extensions with Zen 5, but they still do not have the full AVX-512 set of extensions implemented in a single CPU and neither does Intel. Intel never implemented every single AVX-512 extension in a single CPU:

https://en.wikipedia.org/wiki/AVX-512#CPUs_with_AVX-512

It also took either 4 or 6 years for Intel to fix its downclocking issues, depending on whether you count Rocket Lake as fixing a problem that started in enterprise CPUs, or require Sapphire Rapids to have been released to consider the problem fixed:

https://en.wikipedia.org/wiki/Advanced_Vector_Extensions#Dow...

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Thursday January 09, 2025 @03:22AM (#42643041)
Ok, fair enough, I didn't explain myself very well. What I more specifically meant is that AMD up until zen5 could not

  (1) drive 2x AVX-512 computations
  (2) handle 2x AVX-512 memory loads + 1x AVX-512 memory store
in the same clock.

The latter makes a big impact wrt available memory BW per core, at least when it comes to the workloads whose data is readily available in L0 cache. Intel in these experiments is crushing AMD by a large factor simply because their memory controller design is able to sustain 2x64B loads + 1x64B stores in the same clock. E.g. 642 GB/s (Golden Cove) vs 334 GB/s (zen4) - this is a big difference and this is something that Intel had for ~10 years whereas AMD was able to solve this with zen5, basically only with the end of 2024.

Former one limits the theoretical FLOPS/core capabilities since single AVX-512 FMA operation in zen4 is implemented as two AVX2 uops occupying both FMA slots per clock. This is also big and, again, this is something where Intel had a lead up until zen5.

Wrt downclocking issues, they had a substantial impact with Skylake implementation but with Ice Lake this was a solved issue and this was in 2019. I'm cool with having ~97% of max freq budget available with heavy AVX-512 workloads.

OTOH AMD is also very thin with this sort of information and some experiments show that turbo boost clock frequency on zen4 lowers from one CCD to another CCD [1]. It seems like zen5 exhibits similar behavior [2].

So, although AMD is displaying continuous innovation for the past several years this is only because they had a lot to improve. Their pre-zen (2017) designs were basically crap and could not compete with Intel who OTOH had a very strong CPU design for decades.

I think that the biggest difference in CPU core design really is in the memory controller - this is something Intel will need to find an answer to since AMD matched all the Intel strengths that it was lacking with zen5.

[1] https://chipsandcheese.com/p/amds-zen-4-part-3-system-level-...

[2] https://chipsandcheese.com/p/amds-ryzen-9950x-zen-5-on-deskt...

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Thursday January 09, 2025 @12:16PM (#42647711)
System memory is not able to sustain such memory bandwidth so it seems like a moot point to me. Intel’s CPUs reportedly cannot sustain such memory bandwidth even when it is available:

https://www.ixpug.org/images/docs/ISC23/McCalpin_SPR_BW_limi...

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Thursday January 09, 2025 @01:28PM (#42648460)
Not sure I understood you. You think that AVX-512 workload and store-load BW are irrelevant because main system memory (RAM) cannot keep up with the speed of CPU caches?
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Friday January 10, 2025 @12:30AM (#42652841)
I think the benefits of more AVX-512 stores and loads per cycle is limited because the CPU is bottlenecked internally as shown in the slides from TACC I linked:

https://www.ixpug.org/images/docs/ISC23/McCalpin_SPR_BW_limi...

Your 642 GB/s figure should be for a single Golden Cove core, and it should only take 3 Golden Cove cores to saturate the 1.6 TB/sec HBM2e in Xeon Max, yet internal bottlenecks prevented 56 Golden Cove cores from reaching the 642 GB/s read bandwidth you predicted a single core could reach when measured. Peak read bandwidth was 590 GB/sec when all 56 cores were reading.

According to the slides, peak read bandwidth for a single Golden Cove core in the sapphire rapids CPU that they tested is theoretically 23.6GB/sec and was measured at 22GB/sec.

Chips and Cheese did read bandwidth measurements on a non-HBM2e version of sapphire rapids:

https://chipsandcheese.com/p/a-peek-at-sapphire-rapids

They do not give an exact figure for multithreaded L3 cache bandwidth, but looking at their chart, it is around what TACC measured for HBM2e. For single threaded reads, it is about 32 GB/sec from L3 cache, which is not much better than it was for reads from HBM2e and is presumably the effect of lower latencies for L3 cache. The Chips and Cheese chart also shows that Sapphire Rapids reaches around 450 GB/sec single threaded read bandwidth for L1 cache. That is also significantly below your 642 GB/sec prediction.

The 450 GB/sec bandwidth out of L1 cache is likely a side effect of the low latency L1 accesses, which is the real purpose of L1 cache. Reaching that level of bandwidth out of L1 cache is not likely to be very useful, since bandwidth limited operations will operate on far bigger amounts of memory than fit in cache, especially L1 cache. When L1 cache bandwidth does count, the speed boost will last a maximum of about 180ns, which is negligible.

What bandwidth CPU cores should be able to get based on loads/stores per clock and what bandwidth they actually get are rarely ever in agreement. The difference is often called the Von Neumann bottleneck.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Friday January 10, 2025 @12:19PM (#42657622)
> Your 642 GB/s figure should be for a single Golden Cove core

Correct.

> That is also significantly below your 642 GB/sec prediction.

Not exactly the prediction. It's an extract from one of the Chips and Cheese articles. In particular, the one that covers the architectural details of Golden Cove core and not Sapphire Rapids core. See https://chipsandcheese.com/p/popping-the-hood-on-golden-cove

From that article, their experiment shows that Golden Cove core was able to sustain 642 GB/s in L1 cache with AVX-512.

> They do not give an exact figure for multithreaded L3 cache bandwidth,

They quite literally do - it's in the graph in "Multi-threaded Bandwidth" section. 32-core Xeon Platinum 8480 instance was able to sustain 534 GB/s from L3 cache.

> The Chips and Cheese chart also shows that Sapphire Rapids reaches around 450 GB/sec single threaded read bandwidth for L1 cache.

If you look closely into my comment you're referring to you will see that I explicitly referred to Golden Cove core and not to the Sapphire Rapids core. I am not being pedantic here but they're actually different things.

And yes, Sapphire Rapids reach 450 GB/s in L1 for AVX-512 workloads. But SPR core is also clocked @3.8Ghz which is much much less than what the Golden Cove core is clocked at - @5.2GHz. And this is where the difference of ~200 GB/s comes from.

> Reaching that level of bandwidth out of L1 cache is not likely to be very useful, since bandwidth limited operations will operate on far bigger amounts of memory than fit in cache, especially L1 cache

With that said, both Intel and AMD are limited by the system memory bandwidth and both are somewhere in the range of ~100ns per memory access. The actual BW value will depend on the number of cores per chip but the BW is roughly the same since it heavily depends on the DDR interface and speed.

Does that mean that both Intel and AMD are basically of the same compute capabilities for workloads that do not fit into CPU cache?

And AMD just spent 7 years of their engineering efforts to implement what now looks like a superior CPU cache design and vectorized (SIMD) execution capabilities only to be applicable very few (mostly unimportant in grand scheme of things) workloads that actually fit into the CPU cache?

I'm not sure I follow this reasoning but if true then AMD and Intel have nothing to compete against each other since by the logic of CPU caches being limited in applicability, their designs are equally good for the most $$$ workloads.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by janwas on Friday January 10, 2025 @03:44PM (#42659962)
It is not that the entire working set has to fit within SRAM. Kernels that reuse portions of their inputs several times, such as matmul, can be compute bound and there AMD's AVX-512 shines.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Saturday January 11, 2025 @03:09AM (#42664221)
Parent comment I am responding to is arguing that CPU caches are not that relevant because the CPU for bigger workloads is anyways bottlenecked by the system memory BW. And thus, AVX-512 is irrelevant because it can only provide compute boost for a very small fraction of time (reciprocal to the size of the L1 cache).

I am in disagreement with that obviously.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @03:37AM (#42664360)
Your description of what I told you is nothing like what I wrote at all. Also, the guy here is telling you that AVX-512 shines on compute bound workloads, which is effectively what I have been saying. Try going back and rereading everything.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Saturday January 11, 2025 @04:05AM (#42664477)
Sorry, that's exactly what you said and the reason why we are having this discussion in the first place. I am guilty of being too patient with trolls such as yourself. If you're not a troll, then you're clueless or detached from reality. You're just spitting a bunch of incoherent nonsense and moving goalposts when lacking an argument.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @05:06AM (#42664722)
I am a well known OSS developer with hundreds of commits in OpenZFS and many commits in other projects like Gentoo and the Linux kernel. You keep misreading what I wrote and insist that I said something I did not. The issue is your lack of understanding, not mine.

I said that supporting 2 AVX-512 reads per cycle instead of 1 AVX-512 read per cycle does not actually matter very much for performance. You decided that means I said that AVX-512 does not matter. These are very different things.

If you try to use 2 AVX-512 reads per cycle for some workload (e.g. checksumming, GEMV, memcpy, etcetera), then you are going to be memory bandwidth bound such that the code will run no faster than if it did 1 AVX-512 read per cycle. I have written SIMD accelerated code for CPUs and the CPU being able to issue 2 SIMD reads per cycle would make zero difference for performance in all cases where I would want to use it. The only way 2 AVX-512 reads per cycle would be useful would be if system memory could keep up, but it cannot.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by janwas on Saturday January 11, 2025 @05:31AM (#42664868)
I agree server CPUs are underprovisioned for memBW. Each core's share is 2-4 GB/s, whereas each could easily drive 10 GB/s (Intel) or 20+ (AMD).

I also agree "some" (for example low-arithmetic-intensity) workloads will not benefit from a second L1 read port.

But surely there are other workloads, right? If I want to issue one FMA per cycle, streaming from two arrays, doesn't that require maintaining two loads per cycle?

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @06:37AM (#42665201)
In an ideal situation where your arrays both fit in L1 cache and are in L1 cache, yes. However, in typical real world situations, you will not have them fit in L1 cache and then what will happen after the reads are issued will look like this:

  * Some time passes
  * Load 1 finishes
  * Some time passes
  * Load 2 finishes
  * FMA executes
As we are doing FMA on arrays, this is presumably part of a tight loop. During the first few loop iterations, the CPU core’s memory prefetcher will figure out that you have two linear access patterns and that your code is likely to request the next parts of both arrays. The memory prefetcher will then begin issuing loads before your code does and when the CPU issues a load that has already been issued by the prefetcher, it will begin waiting on the result as if it had issued the load. Internally, the CPU is pipelined, so if it can only issue 1 load per cycle, and there are two loads to be issued, it does not wait for the first load to finish and instead issues the second load on the next cycle. The second load will also begin waiting on a load that was done early by the prefetcher. It does not really matter whether you are issuing the AVX-512 loads in 1 cycle or 2 cycles, because the issue of the loads will occur in the time while we are already waiting for the loads to finish thanks to the prefetcher beginning the loads early.

There is an inherent assumption in this that the loads will finish serially rather than in parallel, and it would seem reasonable to think that the loads will finish in parallel. However, in reality, the loads will finish serially. This is because the hardware is serial. On the 9800X3D, the physical lines connecting the memory to the CPU can only send 128-bits at a time (well, 128-bits that matter for this reasoning; we are ignoring things like transparent ECC that are not relevant for our reasoning). An AVX-512 load needs to wait for 4x 128-bits to be sent over those lines. The result is that even if you issue two AVX-512 reads in a single cycle, one will always finish first and you will still need to wait for the second one.

I realize I did not address L2 cache and L3 cache, but much like system RAM, neither of those will keep up with 2 AVX-512 loads per cycle (or 1 for that matter), so what will happen when things are in L2 or L3 cache will be similar to what happens when loads come from system memory although with less time spent waiting.

It could be that you will end up with the loop finishing a few cycles faster with the 2 AVX-512 read per cycle version (because it could make the memory prefetcher realize the linear access pattern a few cycles faster), but if your loop takes 1 billion cycles to execute, you are not going to notice a savings of a few cycles, which is why I think being able to issue 2 AVX-512 loads instead of 1 in a single cycle does not matter very much.

Does my explanation make sense?

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by janwas on Saturday January 11, 2025 @09:08AM (#42665963)
OK, we agree that L1-resident workloads see a benefit. I also agree with your analysis if the loads actually come from memory.

Let's look at a more interesting case. We have a dataset bigger than L3. We touch a small part of it with one kernel. That is now in L1. Next we do a second kernel where each of the loads of this part are L1 hits. With two L1 ports, the latter is now twice as fast.

Even better, we can work on larger parts of the data such that it still fits in L2. Now, we're going to do the above for each L1-sized piece of the L2. Sure, the initial load from L2 isn't happening as fast as 2x64 bytes per cycle. But still, there are many L1 hits and I'm measuring effective FMA throughput that is _50 times_ as high as the memory bandwidth would allow when only streaming from memory. It's simply a matter of arranging for reuse to be possible, which admittedly does not work with single-pass algorithms like a checksum.

Do you find this reasoning convincing?

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @04:20PM (#42669008)
The purpose of L1 cache is to avoid long round trips to memory. What you describe is L1 cache doing what it is intended to do. Unfortunately, I do not have your code, so it is not clear to me that it benefits from doing 2 AVX-512 loads per cycle.

I am also not sure what CPU this is. On recent AMD processors at the very least, it should be impossible to get FMA throughput that is 50 times higher from L1 cache bandwidth than system memory bandwidth. On the Ryzen 7 9800X3D for example, a single core is limited to about 64GB/sec. 50 times more would be 3.2TB/sec, which is ~5 times faster than possible to load from L1 cache even with 2 AVX-512 loads per cycle.

I wonder if you are describing some sort of GEMM routine, which is a place where 50 times more FMA throughput is possible if you do things in a clever way. GEMM is somewhat weird, since without copying to force things into L1 cache, it does not run at full speed, and memory bandwidth from RAM is always below peak memory bandwidth, even without the memcpy() trick to force things into L1 cache. That excludes the case where you stuff GEMV in GEMM, where it does become memory bandwidth bound.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by janwas on Sunday January 12, 2025 @03:22AM (#42672080)
The code is unfortunately not (yet) open source. The CPU with 50x is an SKX Gold, and it is similar for Zen4. I compute this ratio as #FMA * 4 / total system memory bandwidth. We are indeed not fully memBW bound :)
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Tuesday January 14, 2025 @06:12AM (#42695971)
I'd be curious if you measured 50x on a single core implementation or is the algorithm distributed to multiple cores?

I ask because you say that the results are similar to Zen4 so this would sorta imply that you run and measure single-core implementation? Intel in multi-core load-store looses a lot of bandwidth when compared to Zen3/4/5 since there's a lot of contention going on due to Intel cache architecture.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Friday January 10, 2025 @07:22PM (#42662005)
> They quite literally do - it's in the graph in "Multi-threaded Bandwidth" section. 32-core Xeon Platinum 8480 instance was able to sustain 534 GB/s from L3 cache.

They do not. The chip has 105MB L3 cache and they tested on 128MB of memory. This exceeds the size of L3 cache and thus, it is not a proper test of L3 cache.

> If you look closely into my comment you're referring to you will see that I explicitly referred to Golden Cove core and not to the Sapphire Rapids core. I am not being pedantic here but they're actually different things.

Sapphire Rapids uses Golden Cove cores.

> And yes, Sapphire Rapids reach 450 GB/s in L1 for AVX-512 workloads. But SPR core is also clocked @3.8Ghz which is much much less than what the Golden Cove core is clocked at - @5.2GHz. And this is where the difference of ~200 GB/s comes from.

This would explain the discrepancy between your calculation and the L1 cache performance, although being able to get that level of bandwidth only out of L1 cache is not very useful for the reasons I stated.

> I'm not sure I follow this reasoning but if true then AMD and Intel have nothing to compete against each other since by the logic of CPU caches being limited in applicability, their designs are equally good for the most $$$ workloads.

Your reasoning was that the cores hypothetically being able to load/store AVX-512 faster was important for performance. The reality is that this does not really matter because of bottlenecks in the memory hierarchy. That is why Zen 4 did extremely well on AVX-512 code without the ability to do as many concurrent loads and stores.

Intel and AMD primarily compete in compute bound scenarios where memory bandwidth does not matter. This is why the vast amount of work they do on each CPU generation is designed to increase the amount of compute done per cycle on average (e.g. improved branch predictors, larger reorder buffers, wider cores, decreased memory access times from larger caches and better prefetch, etcetera). There do exist memory bound workloads (e.g. memset, memcpy, checksumming, GEMV, BLAS levels 1 and 2 in general...), but the memory bandwidth from L1 cache rarely matters for them since their working sets are often far too big. While there are still some memory bound operations done on CPUs, they are a small portion of what the CPUs do and the cases where they are not a small portion have long been moved to GPUs (e.g. inference, which primarily uses GEMV for token generation) since GPUs dwarf CPUs in memory bandwidth by 1-2 orders of magnitude.

L1 cache exists for latency and its high memory bandwidth is a side effect of that. Getting high memory bandwidth out of L1 cache does not matter as far as competitiveness goes since working sets are far bigger than the 80KB of L1 cache in Golden Cove. If working sets actually fit in L1 cache for its memory bandwidth to matter, there would be no need for the L2 cache and no need for the huge L3 cache (although perhaps a small cache shared by all cores could make sense). People would not bother building/buying machines with gigabytes or even terabytes of RAM either.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Saturday January 11, 2025 @03:45AM (#42664398)
> They do not. The chip has 105MB L3 cache and they tested on 128MB of memory. This exceeds the size of L3 cache and thus, it is not a proper test of L3 cache.

First, you claimed that there was no L3 BW test. Now, I am not even sure if you're trolling me or lacking knowledge or what at this point?

Please do tell what you consider a "proper test of L3 cache"? And why do you consider their test invalid?

I am curious because triggering 32 physical core threads to run over 32 independent chunks of data (totaling 3G and not 128M) seems like a pretty valid read BW experiment to me.

> Sapphire Rapids uses Golden Cove cores.

Right, but you missed the part that former is configured for the server market and the latter for the client market. Two different things, two different chips, different memory controllers if you wish. That's why you cannot compare one to each other directly without caveats.

Chips and Cheese are actually guilty of doing that but it's because they're lacking more HW to compare against. So some figures that you find in their articles can be misleading if you are not aware of it.

> You seem to view CPU performance as being determined by memory bandwidth rather than computational ability.

But that's what you said trying to refute the fact why Intel was in a lead over AMD up until zen5? You're claiming that AVX-512 workloads and load-store BW are largely irrelevant because CPUs are anyway bottlenecked by the system memory bandwidth.

> That would be true if the primary workload of CPUs were memory bandwidth bound workloads, but it is not since the primary workloads of CPUs is compute bound workloads. Thus, how fast CPUs read from memory does not really matter for CPU workloads.

I am all ears to hear what datacenter workloads you have in mind that are CPU-bound?

Any workload besides the most simplest one is at some point bound by the memory BW.

> The purpose of a CPU’s cache is to reduce the von Neumann bottleneck by cutting memory access latency.

> That way the CPU core spends less time waiting before it can use the data and it can move on to a subsequent calculation.

> How much memory throughput CPUs get from L1 cache is irrelevant to CPU performance outside of exceptional circumstances.

You're contradicting your own claims by saying that cache is there to hide (cut) the latency but then you continue to say that this is irrelevant. Not sure what else to say here.

> but they are truly exceptional since any importan workload where memory bandwidth matters is offloaded to a GPU because a GPU often has 1 to 2 orders of magnitude more memory bandwidth than a CPU.

99% of the datacenter machines are not attached to the GPU. Does that mean that 99% of datacenter workloads are not "truly exceptional" for whatever the definition of that formulation and they are therefore mostly CPU bound?

Or do you think they might be memory-bound but are missing out for not being offloaded to the GPU?

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @04:15AM (#42664513)
> First, you claimed that there was no L3 BW test.

I claimed that they did not provide figures for L3 cache bandwidth. They did not.

> Now, I am not even sure if you're trolling me or lacking knowledge or what at this point?

You really should be grateful that a professional is taking time out of his day to explain things that you clearly do not understand.

> Please do tell what you consider a "proper test of L3 cache"? And why do you consider their test invalid?

You cannot measure L3 cache performance by measuring the bandwidth on a region of memory larger than the L3 cache. What they did is a partially cached test and it does not necessarily reflect the true L3 cache performance.

> I am curious because triggering 32 physical core threads to run over 32 independent chunks of data (totaling 3G and not 128M) seems like a pretty valid read BW experiment to me.

This does not test L3 cache bandwidth at all. This would be a generic memory bandwidth test. Their graphs showing performance at different amounts of memory is designed to show the performance of the memory hierarchy. The moment you exceed the amount of cache at a certain level, the performance transitions to different level. They did benchmarks on different amounts of memory to get the points in their graph and connected them.

> Right, but you missed the part that former is configured for the server market and the latter for the client market. Two different things, two different chips, different memory controllers if you wish. That's why you cannot compare one to each other directly without caveats.

The Xeon Max chips with its HBM2e memory is the one place where 2 AVX-512 loads per cycle could be expected to be useful, but due to internal bottlenecks they are not.

Also, for what it is worth, Intel treats AVX-512 as a server only feature these days, so if you are talking about Intel CPUs and AVX-512, you are talking about servers.

> But that's what you said trying to refute the fact why Intel was in a lead over AMD up until zen5? You're claiming that AVX-512 workloads and load-store BW are largely irrelevant because CPUs are anyway bottlenecked by the system memory bandwidth.

I never claimed AVX-512 workloads were irrelevant. I claimed doing more than 1 load per cycle on AVX-512 was irrelevant because you are going to be bottlenecked on the first load operation for anything that is memory bandwidth bound. Intel losing its lead to AMD is due to entirely different reasons than AVX-512 loads per cycle. This is obvious when you consider that most workloads do not touch AVX-512.

To be clear, when you can use AVX-512, it is useful, but the ability to do 2 loads per cycle does not add to the usefulness very much.

> I am all ears to hear what datacenter workloads you have in mind that are CPU-bound?

Note that I said compute bound, not CPU bound. Nearly all datacenter workloads run on CPUs are compute bound. Memory bandwidth bound things are better run on GPUs, which have far more memory bandwidth.

> Any workload besides the most simplest one is at some point bound by the memory BW.

This is wrong. It does not matter how many experts you consult. Every single one will try to explain the von Neumann bottleneck to you upon hearing this.

> You're contradicting your own claims by saying that cache is there to hide (cut) the latency but then you continue to say that this is irrelevant. Not sure what else to say here.

There is no contradiction. The cache is there to hide latency. It is largely not there to provide bandwidth. It only does as a side effect of being lower latency than system memory. The TACC explanation of how queuing theory applies to CPUs makes it very obvious that memory bandwidth is inversely proportional to memory access times, which is why the cache has more memory bandwidth than system RAM. It is a side effect of the actual purpose, which is to reduce memory latency.

> 99% of the datacenter machines are not attached to the GPU. Does that mean that 99% of datacenter workloads are not "truly exceptional" for whatever the definition of that formulation and they are therefore mostly CPU bound?

99% is a made up number. Your question is nonsensical.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by menaerus on Tuesday January 14, 2025 @05:46AM (#42695822)
You're going a long way not to address reasonably simple questions I had. You're very combative for no obvious reason - I think I had my arguments laid out in the most objective form I could but unfortunately you seem to be very triggered by those especially by the logical concerns I raised. You are in the wrong here simply because you're assuming that all the experience you have is representative of all other experience people have in this industry. There are much larger challenges than designing a filesystem, you know. No need to be so vain.

Not only you're ending up being very disrespectful but you're also pulling out the appeal to authority argument. Also something Brendan Gregg did on me here at HN meaning that no experience can substitute the amount of ego in some guys.

FWIW you can be let assured that you can't match my experience but that's not the argument I would ever pull off. I like to be proved wrong. This is a way I learn new things. BTW I designed my first CPU 15 years ago but during the career I learned to put my ego aside, discuss objectively, think critically and learn on my own reasoning mistakes from other people. Many of these points you are obviously lacking so this is a waste of time for me - I see no way to drive this discussion further but thanks anyway.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by christkv on Tuesday January 07, 2025 @06:40PM (#42629084)
I mean it's like 1/6 of their revenue now and will probably keep sliding in importance over the datacenter. No real competition no matter how we would wish. AMD seems to have given up on the high end and Intel is focusing on the low end (for now, unless they cancel it in the next year or so).
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by davidee on Thursday January 09, 2025 @11:41AM (#42647372)
From what I've seen they've targeted the low end in price, but solid mid-range in performance. It's hard to know if that's a strategy to get started (likely) with price increases down the road or they're really that competitive.

Intel's iGPUs were low end. Battlemage looks firmly mid-range at the moment with between 4060/4070 performance in a lot of cases.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by TrainedMonkey on Tuesday January 07, 2025 @09:33PM (#42630267)
There is one major 4 letter difference - TSMC. Nvidia will get tech process improvements until TSMC can't deliver, and if that happens we have way bigger problems... because Apple will get mad they can't reinvent iPhone again... and will have to make it fun and relatable instead by making it cheaper and plastic again.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by cybercity on Tuesday January 07, 2025 @10:34PM (#42630616)
They already predicted this hence DLSS and other AI magic.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by markhahn on Wednesday January 08, 2025 @10:20AM (#42635131)
Huh? Nvidia does three things well: - They support the software ecosystem - Cuda isn't a moat, but it's certainly an attractive target. - They closely follow fab leaders (and tend not to screw up much on logistics). - They do introduce moderate improvements in hardware design/features, not a lot of silly ones, and tending to buttress their effort to make Cuda a moat.

None of this is magic. None of it is even particularly hard. There's no reason for any of it to get stuck. (Intel's problem was letting the beancounters delay EUV - no reason to expect there to be a similar mis-step from Nvidia.)

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by DanielHB on Thursday January 09, 2025 @07:37AM (#42644683)
As long as TSMC keeps improving die size it will keep getting incremental improvements. These power/thermal improvements are not really that much up to nvidia.

The intel problem was that their foundries couldn't improve the die size while the other foundries kept improving theirs. But technically nvidia can switch foundry if another one proves better than TSMC even though that doesn't seem likely (at least without a major breakthrough not capitalized by ASML).

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by Salgat on Tuesday January 07, 2025 @05:30PM (#42628468)
The 5090's core increase (30%) is actually underwhelming compared to the 3090->4090 increase (60% more), but the real game changer is the memory improvements, both in size and bandwidth.
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by ryao on Saturday January 11, 2025 @07:51AM (#42665521)
They held back. Had they used 32Gbps GDDR7, they would have reached 2.0TB/sec memory bandwidth. 36Gbps GDDR7 would have let them reach 2.25TB/sec. The GB202 also reportedly has significantly more compute cores, TMUs, ROPs, tensor cores and RT cores than the 5090 uses:

https://www.techpowerup.com/gpu-specs/nvidia-gb202.g1072

Maybe there is a RTX 5090 Ti being held in reserve. They could potentially increase the compute on it by 13% and the memory bandwidth on it by 25% versus the 5090.

I wonder if anyone will try to solder 36Gbps GDDR7 chips onto a 5090 and then increase the memory clock manually.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by NoPicklez on Tuesday January 07, 2025 @11:00PM (#42630768)
Jensen did say that in the presentation that compute performance isn't increasing at large enough scales to make enough change. The shift is moving to reliance on using AI to improve performance and there are additions in hardware to accommodate that.

Isn't not being kept a secret, its being openly discussed that they need to leverage AI for better gaming performance.

If you can use AI to go from 40fps to 120fps with near identical quality, then that's still an improvement

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by 7bit on Wednesday January 08, 2025 @04:27AM (#42632473)
DLSS and DLAA are terrible for any high-movement Games Like FPS, racing games, Action Games. I wouldn't exactly call it near identical quality. To shareholders this may ring true, but most gamers know that these GPS gains are not worth it and don't use it.. (They still buy it tho)
Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by NoPicklez on Wednesday January 08, 2025 @05:21PM (#42639120)
That's not true, DLSS isn't terrible for high movement games.

I've been using DLSS for FPS and racing games since I got my 3080 on launch and it works perfectly fine.

Frame gen might be a different story and Nvidia are releasing improvements, but DLSS isn't terrible at all.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by az226 on Wednesday January 08, 2025 @04:34AM (#42632502)
Flops went up 26% and power draw 28%.

So the biggest benefit is PCIe 5 and the faster/more memory (credit going to Micron).

This is one of the worst generational upgrades. They’re doing it to keep profits in the data center business.

Re:Nvidia announces next-gen RTX 5090 and RTX 5080 GPUs by leonewton253 on Thursday January 09, 2025 @09:10PM (#42651793)
not true. They have redesigned AI cores with a dramatically better DLSS4 model that takes advantage of the new cores. Frames have more details and also a third frame can be generated creating a 300% FPS bump.