Originally posted by: The Linuxator
I don't think you have an X800XL there buddy, my A 64 939 gaming rig had an X800XL no issues at all, the only card that form my own experience had a problem with was the Nvidia 6800 (not GT or Ultra) just a plain 6800 PCI-e tried the impossible to get it to work in FC 4 but no go, other than that you shouldn't be running into issues, so I repeat it can't be a driver issue, I had no problem with my X800XL on Fedora Core 4, but there is always room for conflicts with some hardware combinations you might have on your system.
My advice, swap parts around after the install, maybe you will hit the culprit soon, try and remove anything that you do not necissarly need in your system, remove any extra PCI cards, disable all un-necessary onboard stuff one by one (including harddisk controllers if they are not being in use) from BIOS, untill you see what the issue is.