Linux kernel build and 5950X

Hardware CPU
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Hi
I’ve just finished building a 5950X system that I’m going to be using exclusively with Linux. For my Linux machine I’ve jumped from a 2700X to this and I’m noticing a few differences, especially in how quickly it boosts up in frequency and, consequently, in how quickly cpu temp increases. There’s plenty of discussions/reviews/videos about the boosting/thermal “behavior” of the 5950X with gaming and under windows in general. However I couldn’t find much about boosting and thermals under Linux and specifically within the context of kernel building. So I’m looking for other people experiences.
The 5950X is installed on an MSI x570 ACE and I use a Kraken x63.
And this is what I get when I build a Linux kernel with 32 threads:

a) with PBO enabled in the bios the cpu gets to 82C. And in general use I see a very aggressive boosting of core clocks even with normal desktop environment use.

b) with PBO disabled the cpu stays at 65C. Core frequencies still boost but not as high and probably with lower voltages. General use is also very even.

Also consider that right now where I live ambient is like 28C so that’s a factor too.
The kraken x63 seems to be perfectly sufficient to handle the 5950X since even with PBO enabled its liquid temperature never goes above 38C.

I’m fine with keeping PBO off since it doesn’t seem to be improving performance all that much under Linux but at a cost of significantly higher temps. Maybe it’s good for gaming, I don’t know, but I’m not going to be gaming on this machine anyways.

So is there anyone that can share their experiences with temps/boosting within this specific context (Linux in general and kernel building in particular)?

Thanks
John

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With my 3950X I had similar experience. Around 120W power draw without PBO and around 170 with PBO, for a couple percent more performance. If you want significantly more clock without that much of a power draw you have to set the clocks manually.

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The max temps that are still in spec is 90C, so your 5950x is still fine with PBO enabled. I personally wouldn’t worry about it.

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what is the difference in compile time?

I run a 5900x in linux as my daily driver and I have PBO on, but I have been thinking about turning it off because I just dont really need it for most of my games.

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PBO is really not needed for general computing. It is for achieving a single core to boost as high as possible for the greatest framerates in games.

It always pushes way too much voltage and consequently way higher temps than normal computing loads just to get that one core to boost as high as possible.

I never use PBO because I can achieve overall higher core clocks across all cores on my constant workload than PBO ever managed with a manual OC and reasonable voltage.

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I didn’t time them but it couldn’t have been all that much, considering that with pbo and 32 threads I saw about 4.6/4.7 max freq per core whereas without pbo I saw about 4.3. It’s just not worth the increased voltage and temps.

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Yeah, and probably I should look also into undervolting to see how well the silicon lottery went for me. I suspect that that mobo is very aggressive with voltages…

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