This is the commit with which the stutter is introduced: https://gitlab.freedesktop.org/xorg/driver/xf86-video-amdgpu/commit/0d60233d26ec70d4e1faa343b438e33829c6d5e4 (But it seems amdgpu.dc=1 unfortunately is also a bit more vulnerable towards stutter in general when new windows occur, compared to the old display stack.)