Hello,
My RX6800 and (5700xt before that) have the problem, that they can’t reduce the memory clock when they idle, because my monitor (viewsonic vx2758-2kp-mhd) has non standard blanking. Its a known problem, and the fix is to reduce the refresh rate or use a custom edid profile for the monitor.
That works on windows, but on my dualboot Fedora 33 KDE (Kernel 5.10.11, Mesa 20.3.4) neither of those fixes work. And i would prefer not to use around 30 W more power in idle.
I would appreciate if anyone has an idea what I could try out.