Power Supply for Intel 975MB and BFG 7900GTX

[comrade]

I've just bought the basic components for the first computer I've ever built and while I'm still waiting for the E6600, I was checking the other components and I read in the specs for the BFG 7900GTX that it needs a 12v power line that will supply 26 amps.

I was going to buy an Antec 550 watt unit that was supposed to be ATX 2.2 compliant. They were out of that unit and the guy there, (at Fry's), suggested an Antec 500 watt unit and assured me that it will work.

Reading the specs in the book that came with it, says that it supplies 19 amps on the +12v line and I believe it says that it will supply 12 amps on the -12 volt line. (I don't have it in front of me at the moment.) I'm not sure what that means. Will it work with the 7900GTX?

I also found that this unit isn't listed as ATX 2.2 compliant

Do I need to take this unit back and exchange it or will it work reliably?

Thanks for any help provided!

 

[jaguarskx]

I'm assuming the SmartPower 2.0 was recommended to you. It has two 12v rails, one can provide up to 17 amps max, while the other can provide up to 19 amps max. However, the 12v rails will only provide 300w of power or 25 amps max.

Here's the Spec Sheet.

While the Antec PSU only has a total of 25 amps available, it is still powerful enough for the 7900GTX which consumes 86w of power or 7.167 amps. The E6600 at stock speed consumes 58w of power or 4.83 amps (if I remember correctly). That leaves about 13 amps for everything else that draws power from the 12v rails like the hard drives (typically about 2.5 amps for 400GB hard drives), and the DVD-Burner (about 1.5 amps in my opinion).

Don't get too hung over on over ATX12V v2.2 compliance. It's the same as ATX12V v2.0, but requires the PSU to be at least 80% efficient.


If you can buy the Antec NeoHE 500 PSU then do so. It has three 12v rails that can individually provide up to 17 amps each. Combined the 12v rails produces up to 38 amps or 456w of power. More than enough power for the 7900GTX.

Here's the NeoHE 500 Spec Sheet.

The NeoHE series is quiet and since it is up to 85% efficient they meet the ATX12V v2.2 specifications. A highly recommended PSU.

 

[jaguarskx]

Do I need to take this unit back and exchange it or will it work reliably?

Thanks for any help provided!

Sorry, I didn't notice that you already bought it. Anyway, if you can exhange it for the Antec NeoHE 500 then do so. Other than that you'll be fine.

 

[comrade]

Thanks for the advice. I think I'll give it a try and see if it works before trying to exchange it.

(That's assuming the E6600 arrives before the warrantys on the rest of the stuff expire!)