Need help with P5E X48 and Q9550

[spoof]

Ok, i need some advice on this. I'm running P5E Deluxe X48, Intel Q9550 and Fuzion v2+MCR320+MCP655 and 1100Mhz 4x2 G.SKill(F2-8800CL5D-4GBPQ). Pushing to 455FSBx8.5 was everything very sweet - 3.8 isn't that bad for quad. Pushing it up to 4Ghz - 470x8.5 turns to be a problem. The main problem is, that over 455 FSB the OS freezes when it's loading or after 10 minutes under Vista. Strange is that, with 470x8.5@1.425 BIOS vcore, 1.49v NB and PLL 1.60 Prime95 can work for hours. As soon as i stop it, in idle the PC freezes. No error, no high temps, no BSOD, just freezes when is idle.
Today i had no problem for 5-6 hours, bur it turns, that i had push FSB Termination to 1.5 (i don't know how i have done this) and it was rock solid. But this is too much.

So, any advice? 4Ghz is my goal.

[spoof]

Any help?