I have a celeron 300a o/c to 450. It has been quite stable for some time now. I bumped the FSB up to 100 and set the multiplier appropriately. I never changed the settings related to the PCI or AGP bus speeds. I have read some of the message boards which say you have to scale back these settings. Granted, don't have any hardware that uses AGP but was wondering if the hardware I have plugged into the PCI slots will suffer. Also, do I have to worry about the hard disk or ISA slots??? Thanks!