well,if u wanna know the limit of ur proc fsb,firstly,u made a mistake,
u CANNOT use the 8x multiplier,u have to lower down to 6x since u using a E6600,
cause if 500*6 only give u 3GHz which a low vcore can boot ur proc.
follow these step:
1.lower ur multiplier to 6x
2.set ur vcore to 1.35vcore which can be booted for almost E6600 @ 3GHz
3.then set to the FSB that u cant hit which is 485FSB (Natively is 1940MHz) with ur vMCH (chipset voltage) in stock.
4.if u failed to load into windows,lower down to 480MHz (5mhz per time)
5.if it's bootable (lowest FSB that ur chipset able to boot),
6.set to the FSB that unable to boot in BIOS
7.increase ur vMCH to one unit,(let's say ur stock vMCH is 1.5v,if ur mobo smallest unit is 0.05v,set to 1.55vMCH)
8.if booted,then ur stock vMCH for ur E6600 is only 480mhz (if ur 480MHz is the highest u can hit with stock vMCH)
9.then u may play around with 1.55vMCH and see how high the vMCH can hit ur FSB
10.if u increase and unable to boot at 485MHz,increase ur chipset voltage again.
**Remember that it's not advice to increase ur chipset voltage as the heat sink of the chipset is not really ideal for increased vMCH,but u may try since u wanna knwo ur highest FSB that ur mobo and proc can hit
***remember,not MR,but Miss Ace

Good luck bro.
once u hit ur highest FSB,it;s time for u to adjust the multiplier and the vcore.