Originally Posted by spectred
Or when right clicking on a plasma workspace in kde4, for some seconds the menu appears as a corrupted area before it is shown correctly.
I get this too, but it doesn't make any difference if I have desktop effects enabled or disabled (if anything it's worse with desktop effects enabled). I haven't tried playing about with InitialPixmapPlacement or anything. I did file a bug report at KDE wondering if it was anything they were doing:
I'm running an FX 5200. I've found a few people with this problem, as mentioned in the KDE bug report.