For some reason KDE is really slow this morning. Even the mouse lags as it moves around the screen (clearly not 60fps) and all the animations are jerky. top doesn't show anything maxing out the cpu. I've tried changing compositor settings (e.g. using OpenGL) and disabling effects. Also restarting the shell and kwin:
nohup kwin --replace &
killall plasmashell ; kstart plasmashell
Nothing has helped help. I enabled the FPS meter (Show frames per second on desktop?) and rather strangely it is stuck at exactly 24fps. What could be wrong?