Connecting AX850 to Maximus V Formula with two HD7950s

[mandarpalshikar]

Hi guys, I need your help. I'm using AX850 with Maximus V Formula and I'm unable to connect the additional 4 pin EPS connector on motherboard. I'm using 2 HD7950 cards which take up all 4 PCI-E connectors. So this doesn't leave my any connection on back of my AX850 where I can connect the additional 8 pin EPS connector. Please help.

 

[rene13cross]

That doesn't make any sense. ALL included cables should be able to be plugged in at the same time...

I also checked a review just there and yes, all included cables fit into the PSU at the same time.

 

[mandarpalshikar]

For connecting EPS, AX850 has two cables (one of which I've already connected to CPU EPS). And for connecting my 2 GPUs, it has two cables as well. I am having trouble in connecting cable to additional 4 pin connectore provided on Formula.

See this below picture -

In the green box - the right most two have been used for two PCE-e cables for GPUs. The first 8 pin EPS has already been used on one CPU EPS connector on my Formula. Now I need to connect a 8Pin PSU Mating cable to connect to the additional 4pin connector on my Formula.

 

[rene13cross]

The second 8 pin EPS actually has a 10 pin plug that plugs into the 10 pin socket to the left of the green box in your linked picture:

See the 8 pin EPS cable on the left; it has a 10 pin plug.

 

[mandarpalshikar]

There I need to plug in the right most cable in the picture. It has two connectors to go into PSU.

 

[rene13cross]

Huh... So on further research, I found that you're right. You can either plug in the 2 2x6+2pin PCIe power connectors and one 4+4 EPS connector OR 2 4+4 EPS connectors and one 2x6+2pin PCIe connector...

See this video and skip to around 7:47 and you'll see...
https://www.youtube.com/watch?v=8h69gfpDywM

That's a huge design flaw IMO, this is something that they should let you know about more clearly when deciding to buy...

 

[rene13cross]

Huh... So on further research, I found that you're right. You can either plug in the 2 2x6+2pin PCIe power connectors and one 4+4 EPS connector OR 2 4+4 EPS connectors and one 2x6+2pin PCIe connector...

See this video and skip to around 7:47 and you'll see...
https://www.youtube.com/watch?v=8h69gfpDywM

That's a huge design flaw IMO, this is something that they should let you know about more clearly when deciding to buy...

 

[mandarpalshikar]

As a work around this is what I can do -

1. Connect only one PCIe connector for one GPU
2. For second GPU use Molex-to-PCIe converters which come bundled with the card
3. Plug and use the 4+4 EPS Conncetor in the freed slot on PSU

But is it advisable to use molex-to-PCIe converter? Are they reliable?

 

[rene13cross]

As a work around this is what I can do -

1. Connect only one PCIe connector for one GPU
2. For second GPU use Molex-to-PCIe converters which come bundled with the card
3. Plug and use the 4+4 EPS Conncetor in the freed slot on PSU

But is it advisable to use molex-to-PCIe converter? Are they reliable?

There should be no problem with that. I hadn't actually thought of that. They're basically just wires so there's no chance of them "failing" as such...

 

[mandarpalshikar]

I raised a tech support query with corsair and here is the pathetic reply from their side

"Mandar, unfortunately the AX850 will not have enough connectors to accomodate two EPS connectors along with a multi-GPU setup. You would have to upgrade to a HX1050 or a AX1200 in order to have the proper connectors for your system. Sorry for the inconvenience. "

 

[ko888]

You don't need to connect anything to the EATX12V_2 connector unless you're planning on a world record attempt at CPU overclocking using LN2.

 

[mandarpalshikar]

Agreed. But Corsair should really mention this (the problem) on their box or on their product specifications.

 

[ko888]

It's just a cost cutting decision that Corsair made because the majority of their customers don't use a motherboard that requires two CPU power connectors.

You could have purchased the Seasonic X-Series 750W (SS-750KM) instead, on which the Corsair Professional Series Gold AX750 (CMPSU-750AX) is based. That PSU has the missing connector.

 

[mandarpalshikar]

Teh Ram Guy (Corsair Support) suggested me to use this cable as work around -

http://www.newegg.com/Product/Product.aspx?Item=N82E16812198019