This seems to be fixed with amd-staging-drm-next-git for Linux 4.17.
Clocking looks a bit aggressive, but it seems to be really worth it as every
GPU accelerated UI us entirely stutter-free now. Please keep it that way, it
still saves enough power when the system is idle!
I wished the clocking behavior on Windows was the same, I'd consider behavior
on Windows totally broken with partial load (stuttering everywhere).