I've been testing out both the 8GB Pi 4 and the new Pi 400 overclocked to 2.2 GHz. For many things, both are perfectly adequate.

But the slight bit of missing performance (compared to a $300+ low-end celeron or AMD laptop) becomes apparent when you do things like make a video full screen (takes 3-10 seconds), scroll on a JS-heavy page, or have a number of apps open at the same time and switch between them while one of them is doing some heavy processing.

It's definitely tolerable and for the price the Pi is a great little computer. Also as soon as I get a few more CMs, I'm going to run some of my web stuff on them from my home since they're silent, power efficient, and adequate now unlike previous generations.

But it's not necessarily a standard more expensive desktop replacement for the majority of people yet. As it stands today I think this would be a great computer for a family, a kid learning how to type and use a computer, that sort of thing. Additionally, it would be an excellent computer for those who can't afford a $300+ laptop but already have a TV or can pick up a $40 monitor off Craigslist.

> I've been testing out both the 8GB Pi 4 and the new Pi 400 overclocked to 2.2 GHz. For many things, both are perfectly adequate.

I wonder if I'm doing something wrong. I have a 4GiB pi 4B and have found it laggy enough to be basically completely unsuitable for even the most lightweight interactive computing tasks, e.g. basic (ad filtered) web browsing. I think there might have been a bit of intermittent laginess in typing into an xterm in a bare bones tiling window manager with basically nothing else going on, but I'd have to check again. After the initial hickup on full-screening, did the video play back properly for you? For me it was not possible to play 480p youtube videos.

All in all this was much worse than I expected from a quad core machine with 4GiB.

Now I haven't got the fastest micro-SD card, and I'm running with Ubuntu 20.04 64bit server rather than raspian, but is this just what I should expect, or should a different configuration of the 4GiB 4B handle light web surfing and fullscreen video playback?

Ive read multiple reports that the Ubuntu distrivution is significantly slower than the Raspian bundle. I dont know the root cause, but you could check out the stock image for a comparison yourself

How do you actually run compute modules (I assume that's your 'CM' abbreviation above)? Do you need a custom "rack" or something? If so, where do you get them?

Either design your own carrier board or use https://www.raspberrypi.org/products/compute-module-4-io-boa...

Bummer. I would pay good money for a single board that let me mount 4-8 of these guys. I'm aware that the Turing Pi 2 will supposedly do this, but it's still in development.

The CM4 is still a very new product, I know of at least a few other projects that are still on the drawing board. Give it time, I think we'll see some creative adaptations.

For now I'm just using the IO board, and I have a couple more on the way, and I'll rack them up using M2.5 spacers.

Can you list the other projects? What are the advantages of racking CM4s + IO boards vs racking RPI4s? Is it just the extra bit of compute power? In my mind, the biggest draw to the CMs is the prospect of putting them all on one board without having to run cables to each, especially since there aren't multiport USB-C power supplies available that can power multiple RPI4s. Another advantage is the prospect of faster SSD communication.

One of these things stand out. Making a video should take one or two frames. (Milliseconds.)

Something is very wrong with the state of software and GUI. There is nothing inherently slow about making a video full screen, but I understand there is something in todays software pipeline making this a bottleneck.

The Rpi4 plays 720p video full screen at 5% cpu usage (because it has hardware decoding support) - using omxplayer. The hard part is for the hardware decoding support to be enabled in the right places and it seems like kodi is the only place (mpv, vlc don't do it by default)

The other missing piece for the transition to fullscreen is a robust compositor API, such that the same compositional layer can just have its size changed rather than going from app-compositor to system-composited in a new window. Something like, say, Wayland. <insert that whole debate/debacle here>

It absolutely should only take a couple of frames to make a video fullscreen, but to put things into perspective, on my 2015 macbook it takes 3-4 seconds to toggle fullscreen on youtube, and my much more powerful linux desktop isn't much faster.

Have you considered that the compression algorithms for video are nontrivial? I mean I'm sure there can be dedicated hardware for video decoding, but would you put that in a low-cost, low-energy entry-level CPU where you want to shave off as much cost in favor of flexibility?

The Pi is not primarily intended for media consumption. That said, for a similar price to a RPI + display you can get a cheap tablet that will (should?) have dedicated video hardware.

The original Pi CPU was intended for media consumption in set-top-boxes; it was a huge video core with a small ARM on the side.

It has had hardware video decompression for multiple revisions.

In fact it had H264 decoding in all revisions, optional unlockable MPEG2 and VC1(?) up to and including all Pi3 models and H265 since the Pi4.

The regular Pi 4 can run at 2.2 GHz? With external cooling I assume.

Pi 400 is the one with the keyboard and has built in soft-cooling. I wonder what a Raspberry Pi overclocking competition would do.

Look into top end GPU or CPU overclocking on the desktop side of things if you want to know where RPI overclocking would end up. It's going to be the same general thing - get it as cold as possible and ram as much power & voltage as possible as cleanly as possible. It wouldn't end up looking anything like a Raspberry Pi at the end of the day, though, as the first step would be replacing the entire power delivery system (see for example products like https://www.evga.com/articles/01140/evga-epower-v/ on the extreme GPU side of things)

So far no matter what I've tried I can't get beyond 2200 MHz.

Even the Raspberry Pi 400 has hardware decoding where the Raspberry Pi Foundation claims up to H.265 video decoding in 4K @ 60 fps in hardware. That sounds great for all sorts of media and streaming!

However the fine print looks to be that this may not hold true for Chrome and streaming / YouTube, but offline videos with certain players because Chromium doesn't support hardware acceleration for this API. Chromium supports VAAPI, this uses libva. sigh Why does this Linux hardware decoding story always repeat itself. :-(

Still, raw CPU may let it manage at least 1080p at 30 fps but I can't say for sure for anything more.

https://github.com/popcornmix/omxplayer and Kodi are the only ones I've found that handle it correctly (and those are related/share code) - that means Kodi is the only place to play 1080p or larger youtube video (omxplayer can stream video from youtube, but doesn't by itself handle the separate audio and video streams).

Looks like there is a way to enable hardware decoding in Chromium, at least on Raspberry Pi OS:

https://lemariva.com/blog/rss/raspberry-pi-4-video-accelerat...

These days the browser is by far the biggest RAM and CPU hog that runs on my system. All the other native stuff is an order of magnitude faster. It's the main reason I'll be replacing my laptop with a Zen2 or ideally Zen3 one as soon as I can find an adequate model. For everything else the Pi would be ideal but the modern web is incredibly inefficient and browser video very poorly optimized.

I'm hoping for a Pi 400 with a full-size HDMI port, an integrated track pad, an M.2 slot, and at least the option of more RAM.

Adding slots would definitely increase the cost, which makes it slightly less accessible. At the end of the day, this computer is a toy, it has limitations and that's OK.

However, I'm with you on the full-sized HDMI ports. I don't know why they went with dual mini ports instead of one full-sized port? I think that people wanting to run this with dual monitors will be the clear minority. They could have actually reduced cost with one full-size HDMI port, because the HDMI adapter cable would no longer be needed.