CPUs: WHY SO POWER HUNGRY?

We seem to be going through one of those stages where everybody goes mad with their power consumption. But there's no need! Here, let me show you how you can NOT extract all the performance you can out of that expensive new processor you just bought.

0:00 - History of power consumption
3:22 - Why is power consumption increasing?
5:33 - When they went too far
6:20 - The solution

Licensed under Creative Commons: By Attribution 3.0 License

[worldkat]

Overclocking is no longer a trend. I see so many more threads now days on how to undervolt the best for the minimal performance loss. I am currently using my 7950x with the eco mode 65w. I lose 4 fps in my favourite game.

[MrRoko]

Fortunately other popular gaming devices, like handhelds, are pushing in the other direction. I know they don't have a choice but still - it's still mindblowing to me what level of performance I'm getting with my Steam Deck for only 15W TOTAL CPU + GPU (tops at around 25W when we account for display consumation and other internals).

[klad]

You've seen a british man try to chow down a steam deck, now you see him trying to bite through a cpu.

[visualine]

I wish tech press would focus on power efficiency more, gamers nexus are already starting to test this sort of thing which is great, but it's not really done as a standard test which sucks.
edit: realised hardware unboxed also seem to be starting to test power efficiency too :D

[Rachit]

Yeah it has gotten a little out of hand.

Also for GPUs; the RTX 4090 really should have been a 350 watt card but Nvidia wanted that last 2% of performance.

Before 12th gen, Intel’s official power draw was reasonable. But they allowed Z-series motherboard vendors to set unlimited power limits by default, which got progressively worse as they added more cores.

[CyberneticArgumentCreator]

Power envelope for desktop CPUs was a kind of prisoner's dilemma. As soon as either brand moved up, the other brand had to move up or lose. I'm impressed it stayed almost the same from 2010 to 2020, honestly. The "good" news is that they can only really do this once, and then they have to improve IPC/efficiency/process/etc to once again realize gains each generation. And they've now done it. This means the next chipset generations will have to have architecture or process improvements to raise performance.

[electricindigoball]

While you have alluded to this I think it's important to remember that power consumption on its own doesn't tell you if a given CPU is more efficient than another CPU.

For example if you were to compare a CPU with a 60W power limit and a CPU with a 100W power limit but the 100W CPU is able to complete its tasks twice as fast then it is actually more efficient. Efficiency is measured in the amount of Wh required to perform a given amount of work, power consumption is only a part of this metric.

It's also worth considering that a faster CPU can allow you to get more work done in the same amount of time and if you're using your PC to make money then it's possible that those time savings will end up paying for the inefficiency of the CPU.

Regarding the low amount of power pulled by a single core: it has less to do with diminishing returns in terms of performance and more to do with the fact that there's a limited amount of power you can push into a single core before you can't cool it due to thermal density. This was less of an issue in the past because the cores weren't as dense as they are today due to how much the transistors have shrunk.

Finally you have to consider how big of an impact the difference in CPU efficiency will really have on the overall amount of power all of your devices consume (this also heavily depends on your usage as you have to have a workload that will actually stress the CPU before you start seeing those very high power consumption numbers, gaming in particular is known to not stress CPUs all that much). 100W sounds like a lot especially when it comes to CPUs but its impact on the number of Wh you end up consuming could be so small that it's within the margin of error.

Of course I'm not saying that it's not worth it to consider reducing power limits and ideally also undervolting CPUs/GPUs especially since drawing less power also makes cooling a lot easier and could save you a significant amount of money in cooler costs.

[amirmirzaei]

I'm just glad that power consumption is getting more and more attention.

[bbear]

Just yesterday I actually put my 3700X in Eco-Mode, and noticed it was still clocking itself to 4.3 GHz on single cores in games, 100 MHz lower than normal. The only time it really noticeably throttled itself was at full core loads, where the processor capped all its cores to 3.8 GHz. But as a result, my thermals never reached higher than 58 degrees, as compared to PBO mode where my CPU would eventually reach 86 degrees under synthetic load, or even standard mode where it would reach 71 degrees.

I admittedly didn't check the power consumption stats, but I imagine they were also significantly lowered. And then you uploaded this video, letting the world know that it's okay to power limit your CPU if your power draw and thermals are significantly lowered, with a near-single-digit impact on performance. You really laid out why it's more beneficial than keeping it stock. I'd add that if you purposefully play eSports games at 480 Hz and high resolutions, then maybe it can be argued you'll need that extra performance for some games. But that's a small percentage within the enthusiast PC gaming community who mainly use 120-165 Hz, which is already a small portion of the PC community as a whole. The vast majority of people will pretty much only benefit from power limiting/underclocking their processors.

[RealRogerFK]

AMD or Intel could just say "Imagine this scenario: a hot summer, in your room, all windows closed, you're boiling" or something more PR. Also say "Spend less on bills, and more on games" or something, idk. That would sell more than "hurr durr spend 300€ on motherboards"

[gjits]

Probably the most insidious part of this race-to-the-bottom is all the hidden ecosystem costs. Spend more on a cooler, spend more on case/ fans, spend more on power supply... the current dearth of affordable motherboards is partly due to VRM costs. All taken into account you may be spending $100 or $200 more on a build because team purple decided to jump off the performance per watt cliff for 4% higher performance.

[Mulakulu]

As someone who has a 5L case and is very limited on cooling, when i looked at Intels slides, what peaked my interest was that 65W and same performance as previous gen at 240W, because in my case, power efficiency is king. Things aren't as ridiculous as they seem with the high power draws on display because while they technically allow you to suck 400W or whatever, you don't need that. You still get much better performance than the previous generation on the same small cooler. Performance per watt is still increasing.

[nauscakes]

I'm glad to see a video like this. I just upgraded my computer of 6 years, and honestly for playing the games I do like FF14, or Age of Empires 2 -- I wouldn't mind more energy efficient parts.

I'm at a weird point, where I want to upgrade more, because building computers is fun! But I don't need performance, I could easily see myself going down the micro-builds and more efficient route. It'd be really neat to build a computer that has the same performance as my 6 year old ring, but is physically half the size or puts out way less heat.

[gJonii]

I bought 5900x as my cpu, and underclocked it to use about 40W. It's still about 10x faster than my old processor, and I have now cpu that doesn't need cooling. With my (older, I'll upgrade when gpu prices go down to level of sanity) GTX 980 frame-limited during gaming, I'm genuinely unsure if my gaming computer even uses its fans. The quality of life upgrade was massive, and turning the computer on without any sound beside monitors turning on still makes me smile.

[pikaboi]

Nah
I dont see the power trend die out.
People were always willing to spend extra money for little performance gains.
Its not gonna stop just cause their powerbill has an additional 0.

[kajori]

Congrats on being featured in the newest ltt video 👍 folliwing you for years by now and I was very suprised with the ltt staff mentioning your videos

[grimtermite]

When tech reviewers compare cpus price to performance they should include the cost of average power draw for average usage over average lifetime of cpu. Just to help people understand what they will really pay to buy and run that cpu. And of course it would put a big inventive to hardware manufacturers to prioritise power consumption.

[bumi]

in summer It will be impossible to run a computer without air conditioning in the room, especially here in South America.

[xenotiic]

This is very important to me as someone living in a hot climate in a thermally constrained room! Before I lived here, I had more consistent A/C so I didn't need to worry as much about thermals. Now I almost only ever use laptops and game consoles because, despite enjoying the customizability of pc towers and pc gaming, heat output is almost always higher than the other options, which just doesn't make sense in my situation. The recent trends in desktop computing haven't been reassuring either, with the ever higher TDPs. Glad this is getting more attention so someday I can return to computer towers!

[Bebeu]

I love the little small print in the thumbnail