Minimum PSU for crossfire 280x

Solution
Total power draw for the 2 x 280X's will be around 500W.

A 760W should be fine to run those and the rest of your system. However, if you're looking into overclocking that CPU and maybe the 280X's, you'll want something bigger.

Anub1s

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May 27, 2012
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Total power draw for the 2 x 280X's will be around 500W.

A 760W should be fine to run those and the rest of your system. However, if you're looking into overclocking that CPU and maybe the 280X's, you'll want something bigger.
 
Solution

Anub1s

Honorable
May 27, 2012
489
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The 80% ratings are for efficiency, each PSU will supply the rated power to the components. But, depending on the efficiency rating, each will draw a different amount of power from the wall. The difference between amount of power drawn from the wall and how much is supplied to the components is it's efficiency.

So a higher rated 80+ PSU will draw less overall power from the wall while supplying the same 760W (as example) to your components, than a lower rated 80+ PSU.

If you're looking for head room and can wait the time it takes to return the one you have and recieve the new one, I'd personally go with the 860W to give you some room for overclocking.