So bascically I am replacing my PSU so that my computer can properly hold a Radeon 6850 card. My question is, what wattage should I get? Apparently AMD says a 500w PSU is required, but TigerDirect is saying 550w. I was thinking of buying a 600w PSU to be safe, but is that overkill? Here are my specs:
I would get a Corshair http://www.corsair.com/psufinder/ better slightly oversize the wattage as they lose a minimal percentage of power over time (years). The corshair also have overvoltage and undervoltage protection, especially the enthusiast series, that usually prevents the psu blowing the motherboard and components which is always a bonus.
The wattage difference is likely due to wether or not it is an overclocked card or not. Also, that number is padded, so if you are not OCing to the moon then the 550W is probably fine (unless you need a 2nd card).