Is 750w big enough for SLI 680s?

It will do for even for SLI setup of 680 gtx.

Okay. So would 850w be too much then?

- Sam

If you want and have the money, you can buy one with 850w, the 750w will do, but if you want to stay 30% of the max load, get the 850w.
This is with the 680 GTX in SLI in mind.

Okay. Thanks!   Is the corsair HX850 good or is there something else you would recommend?

- Samo

There's the SeaSonic X-850, it's the best psu with 850w.
But that one is also a good one, see what's the cheapest.

Here is Guru3D's power supply recommendation:

GeForce GTX 680 - On your average system the card requires you to have a 550 Watt power supply unit.
GeForce GTX 680 SLI - On your average system the cards require you to have a 750 Watt power supply unit as minimum.

If you are going to overclock GPU or processor, then we do recommend you purchase something with some more stamina. Source http://www.guru3d.com/articles_pages/geforce_gtx_680_re... Agree with above the SeaSonic X-850, it's the best psu with 850w.
But that one is also a good one, see what's the cheapest.

The corsair HX850 is cheaper than the seasonic but only but $30.

- Samo

I will. Thank you for all your help!!

- Samo

Best answer selected by samotage.

id rather get a xfx xxx 750w for 84.99. 670s and 680s dont draw a ton of power, but the 3930k kinda does....