I was in the same boat, so I used the latest "Easy Tune 6" OC'ing app from Giga's site.
I easily clocked an i975 with it, and then with a couple more manual Memory/cpu fine-tuning in BIOS, I was hittin' an i980 in no time.
The trick was knowing the "QPI" limits in conjunction with your CPU and memory limitations/abilities.
But "Easy Tune 6" does a lot of that grunt-work for 'ya.
This board is pretty amazing for "safely" OC'ing compared to OC'ing years back

...anyway, it's a start.