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Help 6pin to 8pin advice PSU to GPU

post #1 of 3
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I have been going through the forums for awhile now looking for solid answers... I get the 75w from 6 pin and 150w from 8 pin. Though my understanding is the 6+2 pin is basically an addition of a ground that (please correct me if im wrong) adds wattage capability. So what is the difference between a 6+2 and a 6 to 8 pin converter which also adds a ground?

I just bought a 980ti which needs 2 8pin connections and I lost all my PSU's spare cables during a move, so I'm left with one VGA cable that has a 6+2 and a 6 pin and I want to use the converter on the residual 6 pin. Whatever research and understanding I have thus far with my 1000w evga g1 PSU (ya I know its overkill... Let's skip that part of the convo). I'm trying to figure if the ONE cable I have is capable of providing the proper amperage to supplyy GPU properly

I imbedded the PSU stats.. Is my understanding that one cable is sufficient? Or will I NEED to spend another $130 just for replacement cables?

post #2 of 3
All the pcie connector have pairs for 12v and grounds connectors, so between the 6pin and 8 pin you have a 12v and a ground. You could tecnically just add the 2 cables to an existing one just doing a Y connection but it will depend on the quality of the cable if will be able to support the current. All the molex to pcie adapter do this. thumb.gif
post #3 of 3
Quote:
Originally Posted by Floo View Post

I have been going through the forums for awhile now looking for solid answers... I get the 75w from 6 pin and 150w from 8 pin. Though my understanding is the 6+2 pin is basically an addition of a ground that (please correct me if im wrong) adds wattage capability. So what is the difference between a 6+2 and a 6 to 8 pin converter which also adds a ground?

I just bought a 980ti which needs 2 8pin connections and I lost all my PSU's spare cables during a move, so I'm left with one VGA cable that has a 6+2 and a 6 pin and I want to use the converter on the residual 6 pin. Whatever research and understanding I have thus far with my 1000w evga g1 PSU (ya I know its overkill... Let's skip that part of the convo). I'm trying to figure if the ONE cable I have is capable of providing the proper amperage to supplyy GPU properly

I imbedded the PSU stats.. Is my understanding that one cable is sufficient? Or will I NEED to spend another $130 just for replacement cables?

First: Theres no (major) difference electrically between a 6+2 plug and an 6 to 8 pin adapter.

Second: A 6 pin and an 8 pin PCI-E power connector both have the same number of electrically live lines (3 +12v, with a varying number of grounds). On the 6 pin, the middle ground is used as a sense line, and the 12v below it is live, although on some crappier PSUs its not. On an 8 pin, all 3 12v lines are live, another ground is added, and there is 2 sense lines for the GPU to use.

see:

As for actually plugging it in, with a PSU like that as long as both PCI-E power sockets on the GPU are occupied by true 6pin connectors it will work. I did it once with a Radeon HD 4870x2, where the second power plug was 8 pin but I only had 2 6 pins, and it ran just fine. I've also done it on an nVidia M2050 Tesla.

Tl;DR make sure both power sockets on the card are filled and you will be good.
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Leviathan
(17 items)
 
Charred
(10 items)
 
 
CPUMotherboardGraphicsGraphics
Xeon E5-2690 Biostar TPower X79 PNY GTX 660 2GB HP GT 440 OEM 
RAMHard DriveHard DriveHard Drive
Gskill Ripjaws 4x2GB 1600mhz Seagate Barracuda 500GB Seagate Barracuda 1.5TB Western Digital Caviar Blue 640GB 
Hard DriveCoolingOSMonitor
Patriot Pyro 60GB Xigmatek Gaia Windows 7 Ultimate Acer S230HL 
MonitorKeyboardPowerCase
Princeton 1280x1024 19" Logitech K120 Seasonic G550 Xclio Nighthawk 
Mouse
Logitech MX310 
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