New PC, do I need a larger power supply to run this graphics set up?

[chambers]

Hey guys,
I'm okay with computers and I've ordered the following set up, and need some advice on power supply and motherboards:

*Intel i7 2600K Quad Core CPU, 3.4 GHz, 8MB Cache,
Socket LGA1155,  32nm, up to 3.8 GHz with turbo boost

*All-in-one Intel H67 Chipset Motherboard
 * Latest B3 Stepping, Trouble FREE
 * Dual Channel DDR3 1333
 * 2 x SATA III 6Gb/s ports & 2 x USB 3.0 ports onboard
 * PCI Express x16 slot
 * Multi VGA Output options: D-Sub, DVI-D and HDMI

*Video Card Upgrade GTX580 1536MB to 3072MB
*upgrade 8GB ram to 12GB ram

Now I've ordered a larger power supply but I'm wondering if 1200W will be enough to run this system.

The 3GB graphics card will chew up alot of power i'm assuming (as this graphics card at 1580 mb already has a reputation for chewing through power).
Would 1000W be enough for all of the above or should I play it safe and go 1200W?
Also, I can upgrade the motherboard from H67 to a Z68 SLI/CrossFireX for $60. Will this make a difference in the current speed or is this really only useful if I want to run another graphics card next to my current on?

Thanks guys.

[Gemini]

1000W will be plenty

Also, you will only see the diffence in speed after adding the 2nd graphics card

[chambers]

would 750 watts be okay? or should i at least get 900 watts?

thanks so much

[Gemini]

i would think that 750 would be okay.However, i think a 900 like this

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371050&Tpk=antec%20900%20watt

would serve you well.

[chambers]

thanks gemini. TP for your help 
really appreciate it.

[greenpride32]

I think you're fine on the PS.  But I would definitely recommend you swap the motherboard.  If you wanted a lower end system with integrated graphics, the all-in-one's are fine.  But they are notorious for causing resource issues when paired with a dedicated graphics card which you are going to be using.  I can't say there will certainly be a problem, but it certainly opens the door for it.  Go Intel or Asus on the mobo.

[chambers]

hey greenpride,
thanks for the feedback.
I actually upgraded the motherboard to a Z68 SLi/crossfire board in case I wanted to add another graphics card in a years time. (I'd probably need to change the power source then too- but I'll do that when the time comes.)
the Z68 should be better than the H67 by a bit i'm assuming?
cheers for advice