Enable all C-powerstates on Leap 15.4 and AMD Ryzen


I have 2 systems with AMD Ryzen CPUs running Leap 15.4. Both systems have a idle power consumption of about 130 W, which is much to much. So I read about Linux and power saving p.a. Power management | System Analysis and Tuning Guide | openSUSE Leap 15.4 and a lot more.
Now I saw, that a
cpupower idle-info gives only these states available: POLL C1 C2

On my notebook running Leap 15.4 too, I get: POLL C1 C1E C3 C6 C7s C8 C9 C10
This device has a Intel(R) Core™ i5-6300U as CPU.

I read all the documentation of my boards to find a missing key, I set processor.max_cstate=6 to grub, but I cannot get a higher c-state than c2.
What I am doing wrong?

Most Ryzen CPUs don’t support other C-states than C1 and C2 if your BIOS doesn’t support it… Make sure you have an up to date BIOS. So if you already checked your BIOS settings there is nothing more you can do…
As you didn’t tell which CPU you are using…AMD CPU’s (the old ones) are known for a high power draw…


Are you sure that your power draw is only caused by the CPU? Old HDD’s, additional cooling systems, graphic card, drives and so on can also cause a high power draw…

Nice discussion from unraid…
I updated my BIOS yesterday. Now I have a dedicated option to enable or disable C6. But my system has only C2.
Maybe that message shows that something goes wrong:

The Kernel in Leap 15.4 is 5.14. It is from September 2021. The Kernel 5.15 had some improvements to AMD power management. It brings the module amd_idle.

After BIOS update load BIOS default settings via menu item.