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PSU with many 8Pin PCI-e

post #1 of 7
Thread Starter 
Hey guys, my MSI lightning 6970 uses 2 8pin PCI-e power plugs. My current power supply only has 3x 6+2 and 3x 6pin connectors on it.

My question is: if i want to (and will) run more than 1 of these gpu's do i need to change PSU to one with more 6+2 connectors or can the card run with a 6+2 and and 6 power connected?? Or in other words can one of the 8 pin plugs on the GPU be powered by a 6 pin plug??confused.gif
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post #2 of 7
Doesn't the card come with molex to 6/8-pin connectors?
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post #3 of 7
I know you can safely use converters to go from 8 to 6 pin, but not sure if it works the other way around due to the higher voltage the 8 pin plugin draws. It seems to be supported on some cards like BFG gtx 280 but yours may want to draw that extra bit and will stutter out under heavy load as an example if you do use converters
Edited by Yumyums - 8/1/11 at 2:56am
post #4 of 7
Quote:
Originally Posted by Ipwnnubletz;14421896 
Doesn't the card come with molex to 6/8-pin connectors?

This x 2
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post #5 of 7
Thread Starter 
Yep good call - there were 2x 8pin to 6pin connectors in the box. Cheers guys.
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FX-8350
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post #6 of 7
Quote:
Originally Posted by als008;14422364 
Yep good call - there were 2x 8pin to 6pin connectors in the box. Cheers guys.

Your two HD6970s need a total of four 8 Pin PCIE connectors.

Your Silent Pro Gold 800W can provide three 6+2 Pin PCIE connectors. This means you will need one more.

One 6 Pin PCIE is rated at 75W while a 8 Pin PCIE is rated at 150W. So, you will need to use an adpater to convert two 6 Pin PCIE connectors to one 8 Pin PCIE connector. I do not think your PSU provides this cable. You need to get a cable like the pic below.
http://www.ebay.com.au/itm/4-Dual-6-Pin-8-Pin-PCI-Express-Power-Adapter-Cable-/250852766614?pt=LH_DefaultDomain_0&hash=item3a67fd7396

Another more complicated option is:-
The standard practice is to convert two 4 Pin Molex to one 6 Pin PCIE.
So, in order to have a properly rated 8 Pin PCIE connector, you need to use four 4 Pin Molex connectors. Such conversion is highly unusual and I do not recommend it.
Edited by windfire - 8/1/11 at 4:59am
post #7 of 7
If your psu is modular you could just buy another 8 pin connector cable.
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