Usually nVidia is on Northbridges as I see it. There are only some that are on South bridges. We can also help you depict what your board is as long as you rprovide us with information on how it looks like. Actually I think Gigabyte has this types of board too? But I don't think it's an ASUS board and I think it is, if I am not mistakened the bios is american phoenix or something like that? Or have I jstu got mixed up?
I know it'll run perfectly fine at this speed, going to test 3.6Ghz next. It's ran those numbers but only for short time period. Hopefully it'll be stable enough to withstand 3.6Ghz as its new idle. 56C Is nothing for another 300mhz ;P
Plus I have a heatsink designed for overclocking the hell out of stuff.