I have a home built system (see details below) for which I am using a PSU from CompUSA that is 300 W. When I have ASUS Probe up and running in the background, I am getting two things. A consistent elevation to 15 Volts on the +12V lead, and the +3.3V drops occasionally to 2.9-3.0 (the 15 volt reading has been there from day one; it's always 12 V in the BIOS, but once I boot up the OS it jumps to 15 and stays there). As a relative newcomer to building systems, I have three questions: 1) is there an easy way to 'eyeball' what wattage would be needed for given components? 2) could a defective power supply cause all of these goofy numbers? 3) Should I believe BIOS or ASUS Probe? Thanks!!!!