[vegardx]

I had a very similar issue with some AMD-based servers (bulldozer, I think) about ten years ago. There was a bug where Xen-based virtual machines could set a C-state on cores it was assigned, but for whatever reason it wasn't able to wake them up. It was fun trying to figure out what the heck was going on.

[icybox]

I have C-states already disabled because of old linux kernel bug where the kernel hang on Zen3 architecture. So not much to see here :)

[nicolaslem]

Do you mean a bug in an old version of linux that is now fixed? Because I have been using Zen3 and Zen3+ on linux since their release and never had to mess with C-states.