I wouldn't assume you can overclock the 5970 to match a 5870. The 5970 uses close to 300 watts. The MB supplies 75, the 6 pin 75 and the 8 pin 150. Total is 300 watts. The more you overclock, the more power you need. I read that in the future, some 5970's will have 2x8 pin connections which will supply an extra 75 watts. This is what ATI had in mind for overclocking the 5970.