Before you up the FSB, lower ram settings, lower the HT speed to 600 from
800, increase vcore, then you should be able to get at least 233MHz FSB.
My old 754 board maxes out with a 233Mhz setting but I have no problems
reaching it. And it doesn't have a PCI lock. The main problem is probably
the HT bus, as it, and the ram, overclocks with the FSB too.