How to enable crossfire with two Gigabyte 7950s? - Page 2 - Overclock.net

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post #11 of 17 Old 04-04-2013, 09:47 PM - Thread Starter
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Originally Posted by Spengler View Post

I did notice that in the original picture you posted but figured it would be a safer bet to rule out other options before recommending a new PSU..

Does you primary GPU work if you use this method to power it?

Either card does not work when being powered through the molex method. So I think that a new power supply might unfortunately be what I need. Any thoughts?

Especially if it's a difference between a AX 850 versus a HX 850 ...

Nevermind, HX 850 doesn't come with 12 pin slots.
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post #12 of 17 Old 04-04-2013, 09:52 PM
 
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If neither card works with the molex method then yeah that's your problem.

From the pictures you posted I see you are using an AX 850 PSU in your computer.. according to the corsair site this PSU is supposed to have 4x PCI-E power connectors.. is yours different?

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post #13 of 17 Old 04-04-2013, 10:20 PM
 
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Quote:
Originally Posted by Spengler View Post

If neither card works with the molex method then yeah that's your problem.

From the pictures you posted I see you are using an AX 850 PSU in your computer.. according to the corsair site this PSU is supposed to have 4x PCI-E power connectors.. is yours different?

I agree...the AX 850 is sufficient to run your 7950 crossfire and that you should have cables to connect both of your cards. You should have all the connectors that you need to setup. If not, just purchase a sleeved corsair cable set.
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post #14 of 17 Old 04-04-2013, 10:28 PM
 
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I would highly recommend ditching the adapters and using the PCI-E power cables that came with the PSU. verify that they are plugged in snugly to the PSU and the cards themselves. You may also want to test each PCI-E lane independently with each card to be sure one isn't faulty. If this doesn't work I would un-install your display driver and see if the system detects both cards, then re-install the driver. Use THIS METHOD to uninstall your CCC display driver and then perform a reinstall of the STABLE 13.1 drivers.

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post #15 of 17 Old 04-11-2013, 12:01 AM - Thread Starter
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Originally Posted by SOCOM_HERO View Post

I would highly recommend ditching the adapters and using the PCI-E power cables that came with the PSU. verify that they are plugged in snugly to the PSU and the cards themselves. You may also want to test each PCI-E lane independently with each card to be sure one isn't faulty. If this doesn't work I would un-install your display driver and see if the system detects both cards, then re-install the driver. Use THIS METHOD to uninstall your CCC display driver and then perform a reinstall of the STABLE 13.1 drivers.

Indeed, I want to try to avoid the molex adapters at all costs, however they don't appear to want to work anyway. I've verified that both PCI-E slots function with either video card. After purchasing the sleeved cable set above, I still find myself not knowing what to do. As it stands now, one of the videocards is currently not being powered but connected to the motherboard. I have a few PCI-E 8 pin (6+2 split) connectors but nowhere to plug them into on the AX 850.

It's the same type of cable that is used to run from the PSU to the two four pin power socket to supply power to the CPU. Also obviously using the same type of cable to connect the first video card. Hopefully this explanation helps to anyone and I'll be happy to provide additional information. I'll see if I can upload photos tomorrow.
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post #16 of 17 Old 04-11-2013, 01:59 AM - Thread Starter
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http://i.minus.com/iXQ6icRmtKJwJ.jpg

http://i.minus.com/ibiJsYiqg67FIE.jpg

http://i.minus.com/it4bQr9NLtzUC.jpg

Some images. Apologies for the subpar photo quality. Do I really need another PSU for Crossfire? :\
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post #17 of 17 Old 04-11-2013, 06:00 PM
 
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Hmm odd, it looks like you've used both sockets on the PSU that you are meant to use for the PCIE power connections

Can you check that you haven't used the EPS/ATX power connector to the motherboard on the power socket meant for the PCIE power connectors?

See below for the which cables to connect where on your PSU:
http://www.corsair.com/en/blog/how-to-install-24pin-and-8pin-cables-on-your-professional-series-gold-psu/

And an example of someone who had connected them incorrectly:
http://forum.corsair.com/v3/showthread.php?t=90043

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