3-4 degrees is acceptable for difference...i see that A LOT!
i got up to 540
FSB but i overlooked disabling "Profile 1" in the the MIT section so i was battling the profile settings while i was trying to adjust the timings manually...all 3 video benches would freeze almost instantaneously upon sarting the bench....i am now re-working the benches at 500
FSB times 8.5 (4250 Mhz)...after i complete all 3 benches, i am tightening up the memory settings to find the lowest memory setting to complete those benches.