That all depends on the brand of Power supply you are looking at. If it is an Antec, Corsair, Seasonic brand then yes its is plenty. There are a few other good manufactures too so list what you are looking at to give you a better answer. But yes 750 watts is more then enough.
That is not a review. It is just a repeat of the distributor advertising. And the specs say a max of 52 amps on the 12 volt rails. 52 amps is a good figure for a 650 watt PSU, but it is pitiful for a 750.
I think what Minitron was trying to say is that if you only need 430W, you don't need to buy a 750W PSU. 430W / 12V = 36A. Any PSU that has the plugs you need to run the GTX580 and has at least 36A on the 12V rail will be fine. My 500W Antec has 34A, so my guess is you'd be fine with most newer 550W or 600W.
Diggle, I never thought I'd get to use this pic, so thank you for allowing me to post it.
If the GTX580 and GTX480 have the same TDP, why does the GTX480 need 42A instead of 40? Why does a GTX460 need 26A and the GT220 needs 30A? Please follow the advice of the pic and either stop posting this cr@p, or do some research and fix the list.
The purpose of the forum is to help those. Which is why diggle "annoys" (for lack of a better word) me so much because the info he gives is wrong. Helping people is great, but telling them they need to buy a PSU larger then they really need isn't helping. A GT220 doesn't need 30A. There are other issues with his list, you just need to sit down and find them.
I agree with minitron. If you don't like my advice, at least take his. (its the same either way.)
I was going to show you cards like the GT220 which doesn't need 30A, or how adding another 2900XT requires only an extra 10A (120W) but somehow needs another 300W for the system, but then it dawned on my you wouldn't listen anyways. I've been trying to tell you for months that your list is messed up and you need to make some changes here and there. But you continue to post, and claim that the list is fine. You obviously won't listen to what I'm trying to get across to you, so I'll just flat out ignore you. (if you feel like listening I'll be happy to point out errors for you to fix.) I will however continue to post that in some cases your list is way off, and provide a more appropriate value for people.