Quote Originally Posted by CryptiK
I used to be very gentle with motherboards until I had my P5B vanilla, I vMCH modded it and ran 1.45v 24/7 through it for 1 year+ and it was fine. Personally I wouldn't hesitate to use 1.4v 24/7 on a P45, 1.5v is about the highest I'd go with vNB on stock cooling. vFSB max is 1.26v, vPLL max is 1.575v, above that is beyond Intel spec and it becomes a guessing game of balancing risk with performance.
I think 1.40v vNB should be fine 24/7 just watch your NB temps.

vPLL should be fine up to 1.8v or more without damaging the mobo, however that is not good for the CPU, keep it under 1.6v at all times.
thx mate