I used the power supply calculator and it came out to be 297 watts. I'm going to use an Athlon XP Barton 2500+ and overclock it to 3200+ speeds. This case that I really like comes with a 380w power supply, so would it be sufficent for the overclocking? I said the processor was a Barton 3000+ when I used the calculator. This can save me some money in the long run and I guess I could upgrade the power supply later if I had to.