I've been having an issue with my P5Q Pro. I've been running at 455mhz FSB and I would keep losing my SATA DVD drive. Reboot and it would be fine for a while. I had one time when my RAID array told me that one of the drives was dead. I rebooted and everything was fine. I dropped it to 433mhz, and I never had an issue with the HDD, but the SATA DVD would still drop every now and then. Dropped it to 400mhz, and have had no issues since. Seems like there is a southbridge issue with the high FSB.