Am running OpenSuSE 11.1 / KDE 3.5 on an Acer Aspire 4730Z laptop. Garbage is displayed on the screen just before and just after the login screen. The garbage sometimes includes vestiges of the taskbar. Suspect some video buffer is not being correctly initialized.
This did happen on 11.1
More in kde4 than kde3
As I recall there was more than 1 reason for it
I think changing the branding packages was one solution. Try searching google or the forum