s3anister

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May 18, 2006
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Another great power supply:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151095
I'd have to vote for the Seasonic power supply. I still have my Seasonic PSU from four years ago churning away in my rig with no issues at all and a killer warranty (even though it's expired now I believe).
 

s3anister

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May 18, 2006
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Yes.
SLi will need 850watts....
Pretty much this. Depending on your setup, with one graphics card most systems will draw 350-400w with CPU+GPU load with higher end systems like X79 possibly approaching 650w overclocked CPU+GPU.

If you plan on running two high end video cards you'll want 850w or higher whereas if you're running a system that doesn't draw much power you might be able to manage with a high end 650-700w PSU (core i5 not overclocked + two radeon 7770s for example).
 
here's guru3d recommendation for power supply for a gtx 480-
http://www.guru3d.com/article/geforce-gtx-470-480-review/13
Recommended Power Supply

Here is Guru3D's power supply recommendation:

GeForce GTX 470

On your average system the card requires you to have a 550 Watt power supply unit. We recommend at least 35 Amps in total available on the +12 volts rails (accumulated).

GeForce GTX 480

On your average system the card requires you to have a 600 Watt power supply unit. We recommend at least 40 Amps in total available on the +12 volts rails (accumulated).

GeForce GTX 400 in SLI

A second card requires you to add another 250 Watts. You need a 850+ Watt power supply unit if you use it in a high-end system (1 KiloWatt recommended). That power supply needs to have (in total accumulated) at least 55 to 60 Amps available on the +12 volt rails.
total amps on +12v rail is the crucial factor.for a single gtx 480,a quality power supply with 40 amps or more is recommended.i would suggest these power supplies-
Corsair TX650 V2(sorry recon-uk :p)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-RSSDailyDeals-_-na-_-na&AID=10521304&PID=4176827&SID=4ha2idjw5f9e
$65 after rebates,seems to be a good deal.it has 53amps which is more than enough for your setup.
xfx pro 650w-
http://www.newegg.com/Product/Product.aspx?Item=N82E16817207014
similar to tx650(both are made by seasonic).
i would suggest going with tx650w,it's one hell of a great power supply.good luck with your build ;)