AMD/ATI have released their latest set of video card drivers for the ATI Radeon line of video cards. New 32 and 64-bit drivers are available for Windows XP. Note that the .NET framework (1.x or 2.0) is required if you want to run these drivers with the Catalyst Control Center.
Could this possibly have been the culprit?
EDIT: Also, about the PEG BIOS controls.
I've found them. Their are a few entries under chipset settings.
- Peg butter length
- Link latency
- PEG root control
- PEG link mode
- Slot power (!) This allows the adjustment of power supplied to the PCI-e slot, this may have been a cause.