I've used a program called
CPUFSB to overclock the FSB on some boards. Some motherboards' BIOSes do not have all the FSB options that the board's clock generator can actually produce. My sister's PC has an old Epox SS7 motherboard, I think it's an MVP3C or something like that. The BIOS supports 100, 112, 133, and 144 options. However, CPUFSB allows for additional settings, like 103MHz. Just know though, the PC will simply lock up dead, at least in my experience, if CPUFSB either uses the wrong clock generator settings, or if the FSB is simply too high. Just have to reboot then, and try something else.