Thanks for the advice, I've left things as follows:
FSB Freq 400MHz (3.6GHz)
CPU voltage 1.29375v
RAM voltage 2.1v (you recommend against... should I revert to "auto"?)
but Prime95 keeps failing on one processor... I've read elsewhere on these forums that 3.6GHz should be easily possible on an E8400 even at stock voltage, so why might mine be failing at a bumped voltage? I have an aftermarket cooler, and when being stress tested temp never exceeds 52 degrees.