Great board, that's what I have... Use the nVIDIA driver kit. Disable things in the BIOS you aren't using and update your BIOS to 1007 (not that that will fix it - It's just best with this board which I consider to still be very fresh).
Verify that you are using the nVIDIA nic and once you have extracted the 6.53 driver kit, perhaps you should go back and (re)install (in case you accidentally bypassed it during the setup):
i have the same motherboard as you folks here. with the 1007bios version i had some problems with the DDR frequency setting. I have two OCZ 512MB Platinum DDR-RAM and i show that the default setting for the DDR frequency is set to "AUTO". In auto mode, the frequency was 330 and not 400MHz. Manually changing the setting to 400MHz and rechanging to "AUTO" fixes this problem, and the 400MHz frequency remains.
Just mentioning it for users with the same motherboard