https://bugs.freedesktop.org/show_bug.cgi?id=106175
--- Comment #30 from bmilreu@gmail.com --- https://github.com/yshui/compton/issues/25 - related to this issue
Some tests me and others did in compton shows there is some relation with vsync issues and the HW cursor. When I turn swcursor on in xorg config both kwin compositor and compton get significantly smoother. Similar behavior is noticeable in some games for me, game stays smooth when playing with keyboard or gamepad then you move the mouse and it starts stuttering hard. With swcursor I get a bit of input lag but smoother performance overall.