The watt budget of a laptop is prohibitive. The watt budget gloves only come off with a desktop.

It's a shame that 2/3rds of Apple's desktop offerings are constrained by that watt budget. iMacs and Mac Minis run on laptop-grade hardware, as I understand.

iMacs run desktop CPUs, but mobile GPUs (which are still pretty fast, but not the fastest).

Apple REALLY needs to come out with a mini-tower Mac supporting desktop graphics cards. And no, I don't mean the new Mac Pro.

Yeah it would be nice to have a headless iMac that you can upgrade that doesn't have server grade components. Right now I'm pessimistic about even the new Mac Pros being upgradable looking at the current iMacs and Macbook Pros.

They could bring back the cube form factor.

I never thought about this. Do laptops perform better when plugged in?

There's a separate line of processors for laptops typically, with Intel it's their U line, which have lower TDP and lower core count by default (i5-XXXXU have 2 cores 4 threads by default, a desktop i5-XXXX will have 4 cores 4 threads).

The prohibitive nature of battery powered devices has pushed Intel's processors to efficient low-powered solutions, but that's a big reason you'll see desktops simply overpowering laptops at the same price range.

Not to say you can never get strong processing in laptops though, they do offer the high-end HQ line which are high TDP mobile processors. Just that the default for Intel mobile processors is "gimped" by design to allow for efficient low-power processing.

Pretty much any laptop with a high-power processor (HQ series) will perform better when plugged in. You can force them to run at higher performance off the battery (go into Power Settings control panel, select "high performance" mode), but they will burn through a battery in like 20 minutes if you're really pushing them.

Sometimes Ultrabook-style laptops will have a higher boost, but they're often thermally limited anyway so running more power just makes them throttle harder.

Some laptops come with a powersupply that isn't good enough to run the CPU on full speed so it will even throttle down when plugged in... (HP I'm looking at you...)

If you have battery power left, it might run faster and drain the battery until it's low and then throttle down. Or just shut down like an older Samsung I saw once.

A lot of laptops, by default, are set to save power significantly more aggressively when running off battery - it's most noticeable when attempting to watch netflix or play games on a cheap laptop.

Yes.

Discovered this recently while working on a GPU-powered ray tracer, plugging my laptop in more than doubled the performance.

Yes but it becomes really noticeable (for me at least) when you get down the the final 5-10% of battery life.

That's probably entirely due to the fresh installation, unless you're doing some very memory intensive stuff and you OCed your DDR4.

I have a 4core/8thread i7 laptop (4630QM) and I cannot get it to throttle after stress testing it for multiple minutes.

The GPU throttles if my thermal paste is getting old and the laptop sits flat on a desk and a game stresses it to 100% all the time. But the CPU I just cannot get to throttle, even with the above conditions being true, unless I remove the paste.

And this is a 13-inch, single fan laptop.

Consider repasting actually, there is no reason your CPU should be throttling.

I can't find much on `4630QM` but a friend of mine bought a laptop from HP that had 4770HQ and it definitely throttled even with the fan at take-off levels.

Hell, especially the (r)macbook pro 15 that I got from my company which had the same 4770HQ - Apple for some reason believes that customers should have their legs burnt and CPU throttled before the fan even spins up.

My bad, had to check the actual laptop order receipt, it's an "Intel Core i7-4710MQ - 2,50 - 3,50GHz 6MB".

Must have it confused with my last laptop's 4/8 i7 product code (which was an i7-3630QM).

The i7-4770HQ is listed as a 2,4 to 3,4 Ghz chip, so there's no reason it should ever throttle in a 15 inch laptop unless the laptop manufacturer messed up real hard (since the same silicon running at a higher frequency, with the same TDP, is adequately cooled by a single tiny fan on a 13 inch laptop).

It's rather unfair to say that laptops generally can't have consumer desktop-level performance on the CPU side, based on a few experiences with specific OEMs.

Now, this changes entirely when 6 and 8 cores are affordable. Desktops make sense again.

depressingly true.

GT840? high-end? laptop high-end is nearly astronomical and still costs premium. I paid 2k for above + 32GB DDR4 + GTX980M.

Oh yes, of course mine was high-end within the category of "business PC laptops", in the grand scheme of things gaming laptops, as you say, are even more expensive but that, if anything, confirms the point I was trying to make.