BIOS tweaking and overclocking
The FB51's BIOS options can be summed up like so: lots of tweaking, not much overclocking. The BIOS presents all the usual options for futzing with memory timings and twiddling with chipset performance settings, but there are only a few basic overclocking options.

Lots of tweaks...

...not many OC tricks

You can key in any bus speed from 100 to 165MHz in 1MHz increments, but there's no CPU multiplier setting (not that those matter with P4s), no PCI/AGP divider option, no CPU or DIMM voltage tweaks, and no way to lock down the PCI bus to a set clock speed. In short, there won't be an SB51G Great Feats of Overclocking trading card. You might be able to wring a few hundred extra megahertz out of a willing Pentium 4, but only if the chip is in an especially nice mood.

I tried overclocking the 2.8GHz chip in our test rig to 3.045GHz on a 145MHz bus, and it booted into Windows XP just fine. However, the system reset as soon as I ran 3DMark. Normally in such a case, I'd throw a few extra tenths of a volt at a processor and bask in the glow of another overclocking success. With the SB51G, I was out of luck.