PSU for 5x7950 Rig

[Ultraviolet]

I've spent a few hours searching but haven't been able to find good answers. How large of a PSU do I need to run a 5x 7950 rig? 1250W or 1500W? If 1500, what are some good models?

Also, can I safely run 1/2 of these on a residential circuit (North America)?

Thanks in advance.

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[Ultraviolet]

Bump

[ewitte]

There was recently a really good deal on an 850W Seasonic.  Using 2x of those shouldn't have any issues.  If your overclocking the 7950 your looking at 300-315W each.  A normal 15A residential circuit without any other high powered devices on it would handle 1/2 the load just fine 10A shouldn't have issues either.

Either way I doubt your going to be able to find a ("affordable") single PSU that can handle all 5 possibly if you run stock and get the best you can find.

[Ultraviolet]

Are they really 300W each? When I spent 2 hours searching here/Reddit/Google most of the replies I saw were that I could expect 200-225-250 each. I'm going to be using the Gigabyte cards with the updated bios.

[ewitte]

IF you heavily overclock them.  With a modest OC you can probably keep them under 250W.  Stock is around 205W.

[Ultraviolet]

Thanks for the help. How can I accurately calculate for the amps on a residential circuit? I'm looking to build a few rigs so I want to make sure I do it right.

[Oldie]

Thanks for the help. How can I accurately calculate for the amps on a residential circuit? I'm looking to build a few rigs so I want to make sure I do it right.

Engineering class... Watts = Amps x Volts, so in your case, Amps=Watts/Volts.  For 300w on a 120v circuit, that draws 2.5a.  On a 20amp circuit, you can theoretically put 2400w

[TheOrri]

You might want to go safe with a seasonic 1250W, the difference in price isn't that great with a 850W.