Comment 16 for bug 366224

I can not only confirm this (IBM (now Lenovo) ThinkPad T60 with a Radeon Mobility x1400), but say that it's not restricted to any one program, theme, or even desktop environment. Firefox, Thunderbird, GIMP, Nautilus, and even the desktop environment itself in certain circumstances (dragging out a selection box, for example) all render minor artifacts.

KDE seems to be affected worse than GNOME - check boxes, radio buttons, and push buttons can be partially hidden behind artifacts. Sometimes an entire text box (a URL bar or the like) or row of icons will be completely obscured by garbage until forced to refresh (selecting, typing, etc.).

Changing AccelMethod in xorg.conf from EXA to XAA seems to fix the issue; however, performance drops dramatically. Simple tasks like opening the main menu or maximizing a window can take a second or two. It is a fix, but the performance loss makes it an unacceptable one - X just uses way too much CPU with XAA to do mundane tasks.