Frequency Scaling on i9 9900, always on max Frequency?

eisalat

New Member
Oct 11, 2020
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Hello,

i built a Proxmox Server with an intel i9 9900 cpu and installed it with the Proxmox ISO.
Unfortunately, i have some Stability issues and think they are related to the CPU running almost always in c7 -State.

I disabled C-States in the Bios but it has no effect at all.

I tried disabling it via boot parameter using this post, but it also doesnt work : https://forum.proxmox.com/threads/r...uf-ex62-nvme-hetzner.63597/page-2#post-294285

i suspect the intel_idle driver doesnt support coffe lake s cpus, but iam not sure if thats really the Problem

Has anyone an idea how to limit c-states to C1 with this CPU ?

Thank you very much.
 
Last edited:
i changed the title because it turnes out my cpu always runs on 5 ghz.

CPUfreq govenor is set to "performance" by default.

I suspect its not getting enough vcore and so it freezes.


How to disable that frequency scaling and let the cpu decide by its own / Bios ?

Thanks!
 
That is simple. Change /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_idle.max_cstate=1 processor.max_cstate=1 audit=0"

after that run update-grub and reboot.
 
i changed the title because it turnes out my cpu always runs on 5 ghz.

CPUfreq govenor is set to "performance" by default.

I suspect its not getting enough vcore and so it freezes.


How to disable that frequency scaling and let the cpu decide by its own / Bios ?

Thanks!

Proxmox sets governor to performance by default which always run on max clock, set it to powersave to enable scaling.

I used a simple cron job, you can also install and configure cpufrequtils

crontab -e
...
@reboot cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver | grep pstate && echo "powersave" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor


But that wont fix your instability, on load it will happen again, limit the clock speed to 4.8ghz or increase vcore in 0.05v steps and test until its stable, i had to increase my vcore quite a bit for 5ghz to be stable on my i9 9900k and i was not satisfied with the temps after that although i use a 360mm aio. Not worth it to go 5ghz on it trust me.
 

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