I have a new Ubuntu 18.04 server on i9-9900KF CPU that I'd like to do some heavy calculations on. Since it has 16 threads, I changed all 16
/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor to performance mode and stopped ondemand service with
sudo systemctl disable ondemand so that it would get stuck after reboot (it does).
The result is puzzling. Before the change (under powersave governor), the frequencies are at 800MHz when idle (as expected by
scaling_min_freq value) and 4700 MHz under load (
scaling_max_freq value is
After the change, the idle frequency is at 5000MHz as expected, but under load, it's again 4700MHz...? So under load it does not matter what the governor setting is, but with performance governor the idle frequency is even higher.
What could be causing this? My power unit should be good for 600W and I have nothing but mother board, dual fan water cooler, M2 SSD and 4-fan case (so I do not think power should be an issue here...?).