https://bugs.freedesktop.org/show_bug.cgi?id=102646
--- Comment #60 from Scias shining.scias@gmail.com --- Still happening on Linux-amd-staging 4.21 unfortunately. Even with VariableRefresh/Freesync working.
I also noticed it doesn't happen if using dual/multiple screens. Looks like the vram clock is forced to the highest state in this case. Is this a normal behavior?