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Tom's Hardware > Forum > Graphic & Displays > Graphics Cards > [Solved] Want to crossfire ATI 5870's, but don't understand PSU connections

[Solved] Want to crossfire ATI 5870's, but don't understand PSU connections

Forum Graphic & Displays : Graphics Cards [Solved] Want to crossfire ATI 5870's, but don't understand PSU connections

Best answer from stuffe.

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I want to add a second ATI 5870 to an existing system. The power supply is 750 Watts and is modular. However, the 5870 requires two 6 pin PSU connectors and the PSU only has two of these. How do I provision the second set of two six pin connectors? I have at least three new modular power supplies and none of them has more than 2 connectors for the graphics cards even though they are all SLI/Crossfire certified.

Thanks!

Reply to mosment
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What power supply is it my friend ?
I don't know your level of understanding but are you by any chance ignoring the 6+2 8 pin connectors ?
PCIE connectors is what they will be labelled anything that says PCIE on it is for the graphics cards.
You can use the 6 pin part of a 6+2 connector just fine.

Mactronix :)

------------------------------ Barbah and Bottsie Boodles
Reply to mactronix

Graphics cards tend to come with Molex to 6-pin adapters in the box. They basically take 2 Molex connectors (the 4 pin white ones if you are unaware) and wire them into a 6-pin for your gfx card. I use a similar setup on my Antec CP-850. If you are in doubt that a Graphics card will have these in the box, go and pick some up from a PC shop, they're easy to come by.

------------------------------ Core i5 2500k @ 5.02ghz 1.51v 8 Hours Prime95 Stable (@ 4.6Ghz 24/7) w/ Phanteks PH-TC14PE, ASUS P8Z68-V-PRO , 8GB Corsair Vengance White, Sapphire R7870 2GB @ 1250/1450, WD Caviar Black 640GB
Reply to deadjon

Thanks, when he gets his lazy whatever out of bed, I'll go check the connectors more carefully. As to type of PSU, I'll have to have a look at it to see. I did just replace my other son's PSU with an OCZ ModXStream 700W pro. It has 2 PCI-E (6 pin and 6+2 pin). Sounds like that one would need a molex to 6 pin. The 5870 takes 2 six pin connectors. If need be, I can swap those two PSU's.

Reply to mosment
Best answer

Be careful to match the outputs where you can. If you have 2 proper ones, and 2 molex adapters, use 1 each for both cards, not 2 proper ones for the first and 2 adapted ones for the other. This will ensure your load is spread evenly if your PSU requires is for it's rail load balancing.

Reply to stuffe

stuffe wrote :

Be careful to match the outputs where you can. If you have 2 proper ones, and 2 molex adapters, use 1 each for both cards, not 2 proper ones for the first and 2 adapted ones for the other. This will ensure your load is spread evenly if your PSU requires is for it's rail load balancing.




+1 Good point.

Mactronix :)

------------------------------ Barbah and Bottsie Boodles
Reply to mactronix

Thanks a lot folks. Upon further inspection the PSU in question has 2 unused 6 pin PCI-E connectors. That makes things a lot easier. Finally got his lazy you know what out of bed!

Reply to mosment

Not a problem glad you are sorted.

Mactronix :)

------------------------------ Barbah and Bottsie Boodles
Reply to mactronix
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