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Same with GPUs - reducing the power budget on a 3080Ti down to like 75% reduced the performance by maybe 5-10% but dramatically reduces noise and heat produced.
What do you use to undervolt your GPU?
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Wouldn't the better solution be to rely on the heatsink temperature instead of on the chip/core temperature then? I mean in the end, the air from the fan is cooling the heat sink, not the chip directly.
Heatsinks don't typically have thermocouples, is the problem.
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> a conservative base rate Do you use windows? I find that with windows the fan is always spinning, even if at low speed. While with linux most of the times it is not spinning at all.
I’m on a Mac - and for the first time a computer I can’t hear (it’s a model with a fan).
I had to throttle my CPU in my macbook or it would shutdown for overheating while compiling.
I don't consider that a feature.
Undervolting with PBO2 should not decrease peformance unless you have done something very wrong.
Ryzen CPUs have limit, max temperature, frequency, power, and voltage. The voltage curve follows a frequency curve so higher clock speed requires a higher voltage. A negative offset in PBO reduces the voltage required for a given frequency. It shifts down the voltage curve. Lower voltage typically means less heat and power draw so you can achive a higher clock speed without hitting temperature, power, or voltage maximums.
If your system is stable when undervolting you don't see a loss in performance, generally it improves because you are able to reach higher clock speeds before running into voltage or power limits. The exception is if you induce a rare issue called clock skew at extreme cases that i'm not even sure you can do with PBO2.
I got annoyed at my fan speeds so decided to experiment with controlling my fans with Python and measuring the results.
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I’m on a Mac - and for the first time a computer I can’t hear (it’s a model with a fan).
Mac tend to run hot to be more silent. I had to throttle my CPU in my macbook or it would shutdown for overheating while compiling. I don't consider that a feature.
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I’m more surprised there aren’t fan controller standards so the mobo or OS can tell the fan to ramp up with usage instead of relying on temperature probes.
There are, you can override your fan speed from the OS. But that leads to issues with a control software crash potentially leaving your fans stuck in a low-speed state. There's pretty much a 1:1 link between CPU load and CPU temperature, so relying on temperature probes is good enough for almost all situations.
That’s why I didn’t talk about user software and was focusing more on mobo (since it knows the current state of all usage and is not os-dependent) or low-level OS hooks which can have battle-tested processes to make sure that the fans are not left uncontrolled. I appreciate you bringing up the point though, it’s vital to make sure the chips don’t fry.
> There's pretty much a 1:1 link between CPU load and CPU temperature
Yes agreed, but there’s a lag time between the two
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What do you use to undervolt your GPU?
On Linux you can use nvidia-smi to set a power target directly in Watts, works well.
Instead you can overclock, which moves the curve to the right (same voltage for a higher frequency), and then add a clock speed limit. You are now running the same frequency at a lower voltage.
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The main problem with the AMD 5000 series is their high idle (non-core) power draw of around 20 to 30W. AMD have reduced this in their 7000 series.
Got any specific numbers? On the Intel side of things, I've seen my 14700K idle at around 5W (which shoots up to 300W under load, I find it greatly amusing) and my 12700H at 0.5W or less.
It's surprising that there are no PC fan controllers that would use some variant of PID control with a temperature target. Traditional fan curves are simple, but the result isn't very intuitive. And many desktop motherboards manage to screw up even the basic fan curve, offering users control of only two points within strict bounds, no piecewise linear curves or hysteresis settings. I started a fan controller project…
PID control isn’t an easy solution in PC cooling. CPU temperatures can swing from 40C to 90C and back in a matter of seconds as loads come and go. Modern fan control algorithms have delays and smoothing for this reason. If you had a steady state load so stable that you could tune around it, setting a fan curve is rather easy and PID is overkill. For normal use where you’re going between idle with the occasional spike…
I suppose the best way would be to try, but my current computers have no (or very unstable) interfaces for fan control.