hi guys...i need help badly...

i can't bring my 45nm quad x3350 on dfi X48 mobo above 420 fsb.

i even lower the multi to 6 , 450 x 6 = 2.7ghz. and the setup can't even boot from bios. i tried to up the NB volt to 1.45v , it was the same result.

what are the possible reasons that caused such limit?

thanks