It totaly depends on your parts if you have PCI and AGP cards that will operate that far out of spec your golden, but most of us are not that lucky, it is possible though. I know people who used to run about those speeds back in the 440BX chipset days and still had stable systems, most modern systems have AGP and PCI locks though so it's not necessary to run these out of spec as it doesn't really offer any pratical benefit.