MrClass wroteThough using an overrated PSU will not cause the PSU to wear out. I am using a 1000watt corsair gold certified PSU to power a single 280X . It is an overkill, but I know I'll have this PSU for a very very long time; it will never get obsolete.
Talk about obsolete. I'm powering a single 7970 on a 1300W Silent Pro. I got it because it was only a few dollars more than the 850W, and was 80 Plus Gold, and it came with a fan controller. Other than that, I had no reason to buy it. I would never go more than 2 GPUs in my system. But oh well.