sorry for this belated reply T,.. i was so damn desperate to make my system stable above 450fsb, it wont boot, try up to 1.46nb and 1.3vtt for 4.050 9x450.. then i read some post here that u have to adjust mchref and clockskew to get higher fsb.. set mchref from 0.65, 0.68, 0.70, 0.72, found that 0.72 is the best spot above 500fsb, tried also from 1000mv to 700mv for clockdrive i found 700mv also the best setting, don't have any idea why.. just trial and error, i've been tweaking since december 08, stressing everyday to find stability, and finally, system now able to run stable at 550fsb, but i had to take out 2 of my ram stick :up:
thx
flo