Currently running Fedora 9 Release to date. Doesn't happen very
often, maybe once every 3-4 days. Twice I've caught it at idle with
the screen saver (picture viewer) frozen and twice while browsing in
Gnome.
Not really noticing anything weird in the logs?
I have had this happen with Fedora 8 on my x86_64 machine. Nothing
recorded in the logs. I have not had the time to debug it.
What kind of motherboard, video card and processor? Maybe there is
something in common with my system.