I am having an annoying problem in Gnome/Gnome-Shell. After some time, like an hour or two, suddenly windows starts moving slower and jerky. When I drag them around they move in steps instead of smoothly. Same thing with maximize and restore, the animations are are jerky and significantly slower. It's like the CPU or graphics card is throttled but I do not see any indication that is the case, and I do not have any process hogging CPU or memory either. All applications run normally as long as I do not move them around. I have also disabled all extensions. If I restart GNOME with "Alt-F2 r" everything is back to normal. For a while that is. I do not have that problem with Unity, but I prefer GNOME so I would like to find out what is going on. Ideas?