6 ms·

Do people who like to play with the voltage and clock speed settings of their CPU/GPU/memory typically do so with one of these utilities? Or in the EFI/BIOS con

by ohazi 6y ago

Do people who like to play with the voltage and clock speed settings of their CPU/GPU/memory typically do so with one of these utilities? Or in the EFI/BIOS config pages? I've never done this, but lately it sounds like there's sometimes quite a lot left on the table, even after part binning. Performance is so high now that I wouldn't bother doing this for an extra 5-10%, but for an extra hour of battery life, it's certainly tempting...

powersnail 6y ago
I've tried undervolting, which did very little for my desktop, but prolonged the battery life and reduce heat noticeably for my Surface Pro. Especially since the Surface was fan-less, the reduction in heat actually helps with performance as well. The only quirk is the BIOS of Surface provides no such options and I have to use intel extreme tuning utility, which crashes sometimes. If Linux gets undervolting support, that will help a bunch of laptops without highly configurable BIOSes.
- bserge 6y ago
  Forget XTU, use Throttlestop. It's amazing what functionality the developer baked into it by mostly trial and error with Intel's hidden MSRs. Linux also has utilities for this, using the same MSRs, although support for a lot of processors is lacking.
bserge 6y ago
Well, it sure would be great if all laptop BIOS had these options. The vast majority don't.
magicalhippo 6y ago
I used to. I found on my AMD 5870 GPU that cutting RAM speed in half had no measurable effect on desktop use, but considerably lowered the temperature of the GPU as a whole, like over 10 C. The GPU itself already did dynamic frequency switching, so not much gain there. So I had a couple of profiles made that I could switch between when gaming and not, which would adjust the RAM speed.
qubex 6y ago
> Performance is so high now that I wouldn’t bother doing this for an extra 5-10% I’m an economist and I’m fascinated by this statement. Surely if something (‘performance’, in this case) is ‘high’ then getting a 5-10% proportion of it is better than getting the same proportion increase in performance on a lesser level (the bigger the baseline, the bigger that 5-10% extra performance is). So it’s apparently irrational: being willing to incur effort (cost) to get something that is worth a smaller amount and being unwilling to do it when the same effort/cost gets you more isn’t what one would expect. But maybe it’s satisficing: maybe formerly the experience was endurable only when running at 110% of maximum, but now there’s no need to redline to get a decent experience? Or maybe it’s the law of diminishing returns, utility approaching some kind of asymptote.
- tgb 6y ago
  If you're running a compute task that is slow and takes an hour, then 5% additional speed saves you 3 minutes. If the computer gets 2x faster, then an additional 5% improvement only saves you 1.5 minutes. So if utility is proportional to time (and hence inversely proportional to speed), then this makes sense.
  - ColanR 6y ago
    To me, that comment and response looks like a microcosm of how economics does, or doesn't, understand its subject matter.
- gravypod 6y ago
  At a large enough N 5% to 10% is massive, at a small enough N 5% to 10% gets you closer to competitive, somewhere between though is where those extra percentage points are "meh". For instance I run my computing on a TR 1950X and I could probably undervolt or overclock the chip but, to be honest, it's not worth the perceived "risk". Undervolting could break specific instructions in undetectable ways and the only way to be sure things haven't broken would be to run something like sandsifter [0] multiple times. Because I, and many others who would have the technical know how, write software on these systems it's not very much worth the headache. If I had a seperate system I built just for gaming or doing a specific task and I wanted to reduce how much I spent, or the power usage, etc undervolting would then shift out of headache -> super worth it. The last thing I want to have to do is run every piece of code I need through godbolt and pray there's no AVX instructions that "may" be fishy. I think this is largely why cloud providers don't do things like this as aggressively. They do it to some extent with custom off-roadmap chips but not controlled dynamically in userspace. If we can get something like this original post into the kernel that would be a massive win for everyone. [0] - https://github.com/xoreaxeaxeax/sandsifter https://github.com/xoreaxeaxeax/sandsifter

by ohazi 6y ago

powersnail 6y ago

I've tried undervolting, which did very little for my desktop, but prolonged the battery life and reduce heat noticeably for my Surface Pro. Especially since the Surface was fan-less, the reduction in heat actually helps with performance as well. The only quirk is the BIOS of Surface provides no such options and I have to use intel extreme tuning utility, which crashes sometimes. If Linux gets undervolting support, that will help a bunch of laptops without highly configurable BIOSes.

bserge 6y ago
Forget XTU, use Throttlestop. It's amazing what functionality the developer baked into it by mostly trial and error with Intel's hidden MSRs. Linux also has utilities for this, using the same MSRs, although support for a lot of processors is lacking.

bserge 6y ago

Well, it sure would be great if all laptop BIOS had these options. The vast majority don't.

magicalhippo 6y ago

I used to. I found on my AMD 5870 GPU that cutting RAM speed in half had no measurable effect on desktop use, but considerably lowered the temperature of the GPU as a whole, like over 10 C. The GPU itself already did dynamic frequency switching, so not much gain there. So I had a couple of profiles made that I could switch between when gaming and not, which would adjust the RAM speed.

qubex 6y ago

> Performance is so high now that I wouldn’t bother doing this for an extra 5-10% I’m an economist and I’m fascinated by this statement. Surely if something (‘performance’, in this case) is ‘high’ then getting a 5-10% proportion of it is better than getting the same proportion increase in performance on a lesser level (the bigger the baseline, the bigger that 5-10% extra performance is). So it’s apparently irrational: being willing to incur effort (cost) to get something that is worth a smaller amount and being unwilling to do it when the same effort/cost gets you more isn’t what one would expect. But maybe it’s satisficing: maybe formerly the experience was endurable only when running at 110% of maximum, but now there’s no need to redline to get a decent experience? Or maybe it’s the law of diminishing returns, utility approaching some kind of asymptote.

tgb 6y ago
If you're running a compute task that is slow and takes an hour, then 5% additional speed saves you 3 minutes. If the computer gets 2x faster, then an additional 5% improvement only saves you 1.5 minutes. So if utility is proportional to time (and hence inversely proportional to speed), then this makes sense.
- ColanR 6y ago
  To me, that comment and response looks like a microcosm of how economics does, or doesn't, understand its subject matter.
gravypod 6y ago
At a large enough N 5% to 10% is massive, at a small enough N 5% to 10% gets you closer to competitive, somewhere between though is where those extra percentage points are "meh". For instance I run my computing on a TR 1950X and I could probably undervolt or overclock the chip but, to be honest, it's not worth the perceived "risk". Undervolting could break specific instructions in undetectable ways and the only way to be sure things haven't broken would be to run something like sandsifter [0] multiple times. Because I, and many others who would have the technical know how, write software on these systems it's not very much worth the headache. If I had a seperate system I built just for gaming or doing a specific task and I wanted to reduce how much I spent, or the power usage, etc undervolting would then shift out of headache -> super worth it. The last thing I want to have to do is run every piece of code I need through godbolt and pray there's no AVX instructions that "may" be fishy. I think this is largely why cloud providers don't do things like this as aggressively. They do it to some extent with custom off-roadmap chips but not controlled dynamically in userspace. If we can get something like this original post into the kernel that would be a massive win for everyone. [0] - https://github.com/xoreaxeaxeax/sandsifter https://github.com/xoreaxeaxeax/sandsifter