Nope, the problem is still there. Could this be some AGP issue?
During boot, the kernel says it cannot find the agpart module, but later on, agpart initializes itself. All is looking fine in X.org log and xvinfo.
Or is it just a bug in the KDE terminal emulator? That's where it happens. But it looks like some hardware issue, a strange line of pixels, changing, at the bottom of the window.
Do I still have to disable the GLX module in xorg.conf?