Comment 6 for bug 362919

I can confirm it does occur on Gnome as well as KDE but not as consistently or so it seemed to me.
I'm using a different machine at the minute so I can't post my xorg.conf but I can give you a brief description of the symptoms.
The contents of a window disappear and get replaced by thin bands of different colours. Sometimes segments of readable windows appear superimposed on top of other windows i.e a piece of a firefox web page will seem to appear inside an open dolphin window or vice-versa. This isn't restricted to windowed areas though, the desktop itself suffers as well. Strangely though, resizing the windows or selecting anything within them brings it back to normal.
If I had to make a wild guess I'd say it's something to do with redrawing damaged screen areas, isn't that xdamage or something that does that?