Well, I have not been able to run Sp32M @+600MHz FSB with this E8600 yet. 590MHz FSB work though and this is the settings I use when I boot at 585MHz FSB:

CPU GTL Ref=0.630v (both of them)
PLL=1.54v
FSB Term.Volt.=1.50v
NB=1.50v
NB GTL Ref=0.550v
CPU clock skew=400 (200)
NB clock skew=200 (normal)

SP1M works above 610MHz FSB.