I don't think so - my psu is 550W, even if it's not a best brand..
I realized another thing though. On the sticker of my RAM says:
256MB 333MHz DDR PC2700 DIMM CL2.5
2.5V
but in my bios there's no option to set lower than 2.6V for the RAM.
also for some reason when I load "Optimal settings" it sets the ram to 266MHz instead of 333. Is that normal?