Which Core2Quad? number or clock speed. Which 540 watt PSU? Make atleast, preferably make and model, there is a lot of variation between power supplies of different manufacturers, raidmax's tend to explode at about 75-85% load, corsairs, seasonics, antecs, and PC P&Cs tend to be perfectly fine even over their rated limit. I cant find any 540 watt PSUs on newegg or tigerdirect so really need to know atleast the make.