(In reply to tempel.julian from comment #108)
> I suppose also the Windows driver enforces maximum VRAM clock in your case
> all the time? If that is true, it would definitely be a cool thing if we
> could get a patch into upstream to cover that as well (Ahzo's patch landed
> in amd-staging-drm-next branch).

I don't have Windows installed on my machine so I don't know.
Anyway the linux driver enforces VRAM clock because of my two monitors are out
of sync, and memory reclockimg causes flickering (if I understand correctly
what driver's code do). 
My patch fixes a bug that breaks this behavior when OverDrive mask is enabled,
nothing more.