Ordered 2x7970, missing one 6-pin PCIE - question!

[smarshallsay]

I'm running a Zalman 1000W (http://www.zalman.co.kr/eng/product/Product_Read.asp?idx=282) but i've lost one of the 6 pin PCIE modular connectors that came with the PSU. So i have 2x 8 pin PCIE and 1x6 pin PCIE.

I have some old molex -> 6-pin PCIE connectors left from older card purchases. Are these safe to use?

I have two that are 2 molex to one PCIE 6 pin but a pin is left out but I think this is fine?
(i checked here - http://www.allpinouts.org/index.php/PCI_Express_(PCIe)_6pin_power)
So with the clip at the top they look like (x is missing)
ooo
oxo

I also have another 6 pin PCIE connector that has all the pins but it only has a single molex.

Can you please recommend me which is best to use?

 

[ALXAndy]

Right from a quick glance.. Your PSU has six rails. I would be very careful mate.

If you load too much onto one rail the amp draw could quite easily pop it..

Do you have a manual that lists how they are distributed and to what connectors?

 

[ALXAndy]

OK let's try and explain this.

Here is how your PSU distributes its power. Note, some of the 12V rails are 18 amp, others are 28. Now, I would imagine the 28a rails are wired for the PCIE lanes, given that a GPU uses more power per amp and watt than any other component.

The issue is that if you use a Molex connector, for example, you could end up putting a whacking great draw on the same rail as say, your CPU, motherboard and so on.

This is a problem, because I would imagine those rails are 18 amp. Running a GPU and CPU and motherboard from a single 18 amp rail is not going to work, and, could endanger your components.

I would personally wait and get in touch with Zalman and order the replacement cable, the correct replacement cable.

 

[Clairvoyant]

email zalman CS and ask them if you can get a spare.

 

[smarshallsay]

Thanks for the replies guys, i found this -

http://www.tomshardware.co.uk/forum/321752-10-enough-power-7970

"For a system using a single Radeon HD 7970 graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 36 Amps or greater and have at least one 6-pin and one 8-pin PCI Express supplementary power connectors."

Forgive my ignorance as I know very little when it comes to electronics but even if it was 2x18A it should be the 36 required and I am assuming that because I will be using the proper 8 pin PCIE cables for the PSU that I will actually get 28+18=46A?

 

[ALXAndy]

Yes but the deal is you are not giving the card 2x18a are you?

There will, no doubt, be other things on those 18a rails.

I had a Corsair CX430 once. It had a 28a single rail. I put an 8800 GTX on it using a molex adapter (because it only had one PCIE 6 pin, for a reason !) and it just kept looping at post and rebooting itself.

Honestly man, for the sake of £900 worth of cards, have a little patience and contact Zalman and use the correct connectors.

 

[smarshallsay]

Will do. Thanks for your help

 

[smarshallsay]

Cannibalised the corpse of an old PC i found in my loft that had a 700W modular Jeantech PSU, cable looks to be the same as the one for the Zalman so I'll take my chances with it. Thanks again for all the advice