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Electr0

Powering A Second GPU

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Hey All.

 

So I currently have a Corsair HX620 and running one 7970, which is being powered by both of the PSU's PCIe power connectors - once 6 pin and one 8 pin.

 

I've done some research and calcs I think my PSU will have enough power to run a second 7970, however I'm not sure it I can power it, physically.

 

Since both of the PCIe power connectors are in use, I would need to use the 2-Molex-to-6-Pin and the 2-Molex-to-8-Pin power connectors that came with my original 7970.

 

My question is: Since I will need the equivalent of 4 Molex connectors, can I power two of them off one 5-pin connection and two of another 5-pin connection - see the top row of connectors on the 3rd image down here.

 

I would much prefer to do this than have to lay out another $300 odd for a new PSU.

Edited by Electr0

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My question is: Since I will need the equivalent of 4 Molex connectors, can I power two of them off one 5-pin connection and two of another 5-pin connection - see the top row of connectors on the 3rd image down here.

 

I would much prefer to do this than have to lay out another $300 odd for a new PSU.

Yep that's no problem assuming the PSU can cope.

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your old overclocked i7 920 will suck a bit more juice than newer cpu

when you get the 7970 undervolt them both i ran mine at 1112mv at which they did over 1000mhz using less power than the default of 1175mv 925mhz or 1225mv on boost cards

cheap molex adapters have been known to make a lose connection getting hot and burning the wires\connections around them so just make sure there on snug and dont get warm

 

but if that review is correct that the psu is split rail with everything but the 24 pin and atx 4 pin connectors running from one 25-26a ~305w 12v rail im afraid i dont think you have a hope unless you can use the 4 pin 12v connector to run the mb instead of the 8 pin eps and underclock the cards to 7950 speeds 800mhz then just maybe you will sneak it in if your careful to keep games locked at under 60fps

 

the up side is you dont need to spend $300 on a new psu this one is only $125 its no seasonic x but then its $100 cheaper http://www.hardwaresecrets.com/article/In-...y-Review/1726/1

it should have enough power to run your pc comfortably provided you dont really crank the v when overclocking

with your cpu\mb and overclocking the ideal psu would be ~850w to keep it cool and quiet while leaving room for extras

Edited by Dasa

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Thanks for the replies guys.

 

Hmm, that a bit annoying. I don't really like the idea of under clocking my GPUs just to make them both work. It seems like a bit of a moot point.

I guess I will be needing that new PSU after all.

 

I've been looking at getting the AX860i. It has a great reviews and it Platinum certified. It's going for about $315 atm. I could get it via Amazon for $280 (inc. shipping) but then I would have to contend with an overseas RMA if anything ever went wrong :(

 

Maybe I'll just have to wait another fortnight for my next pay cheque so I can get the GPU and PSU.

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