# Difference between CPU 8-pin and GPU 8-pin?



## Trackr (Dec 20, 2011)

I need both an 8-pin GPU extension cable and an 8-pin CPU extension cable.

Problem is, I can't tell them apart, and no website correctly identifies which one they're selling!

Any help?


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## scaminatrix (Dec 20, 2011)

Search for "12v EPS Extension" to find CPU extension cables, and
search for "8-pin PCI Express Extension" to find GPU cables

These are the identifiers, if you're not comfy with trial and error then just use these 

CPU

GPU

If you link to your preferred e-tailer, I'll help you identify them if you like?


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## Arctucas (Dec 20, 2011)

Molex technical drawings:

EPS-http://www.molex.com/pdm_docs/sd/039012080_sd.pdf


PCI-E-http://www.molex.com/pdm_docs/sd/455870002_sd.pdf (third generation polarization)

Notice the difference in the keying.


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## Athlon2K15 (Dec 20, 2011)

cpu 8pin has 4 power 4 ground  8pin gpu has 3 power 5 grounds


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## xaira (Dec 20, 2011)

an 8 pin pci express extension is for the gpu 

an 8 pin EPS exension is for the cpu


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## cadaveca (Dec 20, 2011)

AthlonX2 said:


> cpu 8pin has 4 power 4 ground  8pin gpu has 3 power 5 grounds



Not exactly.

8-pin GPU has 3x12v, 3x ground, and two "sense"/ground. 

Meanwhile, 6-pin GPU has 3x 12v, 2x ground, 1x sense/ground.








A CPU 8-pin has 4x 12v, and 4x ground.


Each has 12v on "opposite" pins, and are keyed differently, so confusing the two should be pretty easy...8-pin PCIe plug inserted into 8-pin CPU receptacle should be very hard to do, and vice versa.

Anyway, if you look at the plug itself, and where the clip is, you can determine which is one. One has 12v lines near the clip, the other does not. CPU plug has 12v near the clip.


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## Arctucas (Dec 20, 2011)

cadaveca said:


> <SNIP>
> 
> Anyway, if you look at the plug itself, and where the clip is, you can determine which is one. One has 12v lines near the clip, the other does not. CPU plug has 12v near the clip.



Which is easy if your PSU has colored wires. 

My PSU, on the other hand, has ribbon cables, which makes identifying a given individual conductor impossible by merely looking at it.


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## cadaveca (Dec 20, 2011)

OK.

Then:

Clipside pins...square plugs on outside 2 plugs= GPU, square plugs on inside 2 plugs = CPU.


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## Arctucas (Dec 20, 2011)

cadaveca said:


> OK.
> 
> Then:
> 
> Clipside pins...square plugs on outside 2 plugs= GPU, <SNIP>





No.


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## cadaveca (Dec 20, 2011)

Ha. Whoops. Weird. The drawings by Molex above and my cables for the CPU are the same as the Molex drawing, so I assumed the drawing for the GPU plug was right too. I guess there's more than one type of connector, or something. 


Anyway, that's a GPU 8-pin in that pic. The two boxes on the right are joined together to prevent insertion into CPU 8-pin plugs(modular 6+2 conector should have that as well).


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## Arctucas (Dec 20, 2011)

On the Molex drawing I referenced, there are three generations of this connector. The third generation is the one:


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## DaMobsta (Dec 21, 2011)

If it helps, if a connector is a 4pin+4pin then surely it's for the CPU. If it's 6pin+2pin then it's pcie. That is if you can get connectors that are designed like that


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