GTX 470

Considering one takes about 230Watts? I'd be guessing 900W. Then 200W for an OC'd processor, you're looking at 1.1kw of pure 12v power.

I would recommend no less than a 1200 watt PSU with PLENTY of amperage on those 12v rails, I'd probably suggest a 1500 watt.

Something like this:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

A 1200w should be enough, Guru3D were using 794w in total when they tested 3 - way 470 SLi and that was with a Core i7 965 overclocked to 3.75 GHz.

I'm trying to decide which video card would be best for this pc:

Core i7 980X
24GB DDR3 1600 Corsair Dominator
EVGA X58 3-Way SLI MOBO
Ultra 1200w PSU
Coolermaster HAF-X case

Thanks much also would it be best to use EVGA brand vid cards on a EVGA mobo?

The best would be 3x GTX480's but what does your budget allow for? And it won't make any difference what manufactures cards you use with your motherboard.

More money than sense? 24GB of RAM!!

You seem to have no shortage of cash so why not go for 4 x GTX480's and a 1500W silverstone PSU.

it doesn't make any difference what make your GPU's or mobo is.