I upgraded to 9.4 with architecture x86_64 just yesterday. I noticed some artifacts with XFCE 4.6 and Firefox 3.0.8. When I click "Log Out" and the small window appears with the choices to restart, shut-down on the screen I have some small horizontal short black lines spreaded on the screen. Inside firefox I get some portion of the page with black background that disappears if I scroll the page up and down.

Have you noticed such artifacts?