Anyone have any experience with *UNDER*clocking a CPU to control for thermals?

[SpecialKO]

My work just ordered me an MSI GS65, and while I'm pretty pumped, I've heard a lot that it (and the other thin-and-light gaming laptops with 8th-gen intel CPUs) get really hot under load and:

1)Throttle super hard, and
2) regularly hit 95-100C in internal temperatures, which has some consequences to long-term component health

Some of those same places where this is being discussed also regularly talk about using either Throttlestop or Intel XTU to undervolt the CPU to preemptively deal with thermals for a minimal drop in processor speed in exchange for much lower internal temps. I mentioned this as a possibility to an EE friend of mine, and he said that while it wasn't as obviously risky as overclocking, undervolting was still bad for the components, and if reduced thermals was my goal, I would be better off going into the BIOS and lowering the max clock speed and/or turning off Turbo.

Any thoughts? I'm generally inclined to believe my buddy on this kind of thing, but he's also not part of the mad overclocker crowd.

 

[PatrThom]

There's nothing wrong with undervolting your CPU, unless undervolting your CPU also means undervolting some of your other components as well. Undervolting is one of those things that cryptominers do all the time in order to reduce power consumption (and therefore their bottom line). The same goes for GPUs.

Underclocking and undervolting are two things you don't hear about much, because people usually don't care as much about things that reduce their performance, but it's perfectly fine, and is in fact part of the process that CPU manufacturers use to "bin" their parts into the different categories, such that a part that performs well when undervolted or underclocked may get binned as an -L (low-power) CPU.

--Patrick

 

[strawman]

Not on recent hardware, no, but you can do both. Just keep in mind that you'll have about the same latitude going down as up - you're not going to have a lot of luck clocking a 4GHz chip at 3GHz because the timing requirements won't be met in certain subscircuits within the processor.

Use the same process as overclocking - rigorous testing - and you can have a reasonably stable PC that's underclocked and undervolted.

 

[PatrThom]

Just keep in mind that you'll have about the same latitude going down as up - you're not going to have a lot of luck clocking a 4GHz chip at 3GHz because the timing requirements won't be met in certain subscircuits within the processor.

I forgot to mention that. Yes, there are limits below which the chip will have trouble functioning, but you should notice your computer is becoming less stable and therefore should be moved back up a notch or two. Almost paradoxically, if you reduce clock speed to the point where your system starts to become unstable, giving the processor a slight increase in voltage may help restore stability, though it's up to you to determine whether or not the net savings in power/heat is worth that tradeoff.

Keep in mind that power consumption/heat generation of processors (both CPU and GPU) is logarithmic (hockey stick-ish), and so yes, you're likely going to hit a point where further reductions in clock speed/voltage don't make as much of a difference in power/heat. But that's perfectly fine, because that's the indication that you've reached a good stopping point for your experimentation.

--Patrick

 

[SpecialKO]

Would you recommend any particular starting point? Or just drop by 5 mV, run a stress test and play a performance-dependent game for two hours, and then repeat if nothing crashes and HWMonitor doesn't show anything weird?

 

[SpecialKO]

I'm being more serious about this than I normally would because our IT dept only replaces laptops every 4 years, and the last time I had a laptop with desktop-class chips and a dGPU in it, the heat baked the insides after 1.5 years. We ordered from Xotic with a nice Xotic lifetime support thing, but that's obviously not a match to being able to walk into the Apple store and walk out again with a brand new laptop at no charge.

 

[PatrThom]

If you're most concerned about heat, then focus your efforts on the GPU. Those tend to get WAAAY hotter than CPUs, especially during gaming. It might mean -10FPS, but it also might mean +2yrs of service.

--Patrick

 

[SpecialKO]

MSI's OEM software should take care of underclocking the GPU, if it comes to that, fairly easily, so I'm not too concerned about that one.

EDIT: In a perfect world, I'd like both to peak at 85 C, and average (under load) around 80 C. That should be well within tolerances for the purposes of longevity. But we'll see what happens.

 

[PatrThom]

Xxerclocking is always a crap shoot, just experiment until you're comfortable, or at least until you achieve your best possible result.

--Patrick