freezing screens

[Koen Hufkens <khuf mail dma be>]

I don't think this is really a gnome related problem, but pretty often
my screen goes blank. All I see are just some lines in the colors of my
desktop. This lasts for about half a minute, it disappears in thin air,
but with my next mousecursor move my screen freezes like you would
expect a screen to freeze.  After a second It's gone and I continue
doing whatever I was doing. Don't know why? Any ideas?

I'm currently running, redhat 6.0 on an AMD K6-2 3dnow cpu, 128mb ram,
quantum fireball ex 6.4 GB HD and a VirgeDX2 4mb videocard.

Koen.