I'm assuming you have the Q6600 and am reading your motherboard manual.
In your BIOS screen, Frequency Voltage Control / FSB memory config /
1. FSB memory clock mode should be UNLINKED
2. Try to set FSB QDR to 1333.
Save and hopefully when Windows boots you're running at 3.0 GHz.
If not, you may have to go back to BIOS System Voltages and bump up the CPU Core and CPU FSB.
Here's another thread. I hope this helps you.http://www.youtube.com/results?search_type=&search_query=evga+750i+ftw+overclocking&aq=6&oq=EVGA+750