Created attachment 160164 [details]
system specs (inxi)

Aloha !

KWin appears to cause dropped frames and heavy stuttering in games or graphical applications such as video players, OBS, Blender, etc, whenever compositing is enabled. This behavior disappears when compositing is disabled.

Games ran while compositing is enabled suffer from a significant drop in FPS and heavy stuttering. Movements appears not smooth, as if every few frames were dropped or swapped. This is also visible by using gltest (https://git.ralfj.de/gltest.git), altho the system needs to be somewhat loaded to really exhibit the issue.

I have tried disabling KWin's vsync by setting the following :
KWIN_X11_REFRESH_RATE=144000
KWIN_X11_NO_SYNC_TO_VBLANK=1
KWIN_X11_FORCE_SOFTWARE_VSYNC=1

This, however, did not solve the problem.