too bad for that quad, I think you should test the scores with the E6600 at 3.8GHz and compare them with your G0, then see if E6600 wins by a small margin, take the G0, if it wins by quite more, use the E6600.
oh, and also you can try upping the FSB from 3.5GHz one (1) step at the time and see where it doesn't want to go more HTH