The Amount of Power Needed

[fluxer5]

Hey Guys,
I am looking to build my own PC, but I am undecided on the amount of power I need. My current choice is an Antec 850W:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371009

Please help me at least ballpark how much power I would need, possibly even recommend a PSU. This is my PC:

Asus P6T-Deluxe Motherboard
Intel Core i7 920 (Overclocked to 3.6GHz)
EVGA Geforce GTX 280
G.SKILL 6GB DDR3 Triple Channel
Ultra MD2 Card Reader
Creative Labs Sound Blaster X-Fi XtremeGamer

Thank you and your input is greatly appreciated.

[Obsidian]

An Antec Neo Power 500 or Antec Earthwatts 500 would power a single GTX 280 rig with power to spare.

[fluxer5]

Thanks, i did not realize that I overestimated so much. I used the Power Supply Calculators but the number seemed too low -- I thought I was missing something. Would you know if 850W is enough for Dual Sli 280?

[crazybus]

The Antec 850w should easily power a dual GTX 280 system. If modular cables aren't a big deal also consider the PC Power & Cooling Silencer 750 Quad or Corsair 750TX.