
Phoronix is good resource on coverage for this component. The AMD CPU cppc driver (amd_pstate) is a kernel module.
Fedora would be one of the better fixed-release distros with this in mind (this is what I use personally so I may be biased). Faster still would be arch + derivs but that may incur some additional learning and care to use properly.
Think of the system firmware (SBIOS) and kernel and user spaces as different environments, the work on these components will target different aspects of your system. I would encourage keeping your BIOS up to date, particularly as these may ship critical HW and security fixes.
e: it appears there’s a sysfs interface specifically for the 3D cache:
Could be a prod ready engineering sample. They get around more than you may think.