# Cable Sleeving/Wire Guide for PCI-E 8-pin



## Lopez0101 (May 30, 2015)

Hey all,

I tried googling some but couldn't find anything specific to what I'm looking to do. I want to sleeve and make custom lengths out of the stock wires that came with my PSU (SeaSonic SS-660XP Platnium). When it comes to the PCI-E, I want to make the 6+2 cable a straight up 8 cable; however, I want to make sure this is even possible without having to go the 6+2 route. 

The modular plugs on the PSU don't seem to be bespoke, standard molex connectors. However, the CPU EPS cable plugs into the same slots as the PCI-E and I know the EPS has 4 12v wires while the PCI-E has 3. So, would a wire going from that additional 12v into the PCI-E 8 pin just toast the card? I'm guessing yes, so is it even possible to make a true 8 cable 8pin PCI-E from the PSU without having to use an extension or the 6+2 setup?


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## Norton (May 30, 2015)

Lots of info on this subject in this thread from overclock.net:

http://www.overclock.net/t/1420796/repository-of-power-supply-pin-outs


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## Lopez0101 (May 30, 2015)

Hmm, don't have the 8-pin for my PSU. Doesn't really cover going 8 to 8 PCI-E. Hmm...


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## 2big2fail (May 31, 2015)

I have Corsair AX850, re-branded Seasonic. It is most likely almost identical to this (Seasonic P1000) on the PSU side:



Spoiler: PSU












The 8 pin and 12 pin connectors are almost always a row of GND and a row of 12v.

Use a multimeter to check your [PSU] 8 pin/12pin <==> 6+2 [VGA]:



Spoiler: EPS PWR & PCIE PWR


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## Lopez0101 (May 31, 2015)

Hmm, I don't have a multimeter, so I guess I'll just have to do a double wire and see if I can find a soldering iron at work to borrow.


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## 2big2fail (Jun 1, 2015)

Lopez0101 said:


> Hmm, I don't have a multimeter, so I guess I'll just have to do a double wire and see if I can find a soldering iron at work to borrow.



Before you do any wiring, always ALWAYS make a note or a spreadsheet of the cable pinouts you have. Even if you find a helpful person like myself give you a pinout diagram, I could have made a mistake or posted something out of date. ALWAYS use a multimeter to make sure the diagram you find on the internet matches the power supply & cables you have. If you have access to a soldering iron at work, you must have access to a multimeter too. If not, just spend the $20 to get a multimeter at your local electronics store or newegg or whatever. Believe me, its worth it because you are also going to want to double check the wires you make to make sure they are identical to the PSU cables. The last thing you want to do is fry your graphics card or motherboard by short circuiting a connection.


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## theonedub (Jun 1, 2015)

I literally just finished soldering together 2 molex to PCIe 6-pin adapters into one dual molex to dual PCIe 6-pin and I goofed the wiring. I went to test continuity with my dvm and got nothing. Turns out I wired one PCIe cables 12v (Pin1) to the other PCIe cables 12v (Pin3) then sent that to Pin1 on a molex cable. I repeated that mistake for every wire. The right pins still get 12v, ground, and sense- think it will still work?

/threadjack but hopefully reading this will remind you to double check your wiring before you get to soldering


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## Lopez0101 (Jun 1, 2015)

I was going to make my own diagram, of course, I was more interested in seeing if anybody had the PSU side layouts since I wanted to make an 8-pin PCI-E cable instead of a 6+2 without just making an extension; I'm already trying to have less cabling in my mid-tower. However, because the PSU side also uses the PCI-E for EPS, it seems one full row is +12v leads. So I just meant sucking it up and soldering the doubles wires that go to the +2 on the 6+2 PCI-E plug. I'll just make the split far enough down that I can hide the Y split.


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## 2big2fail (Jun 3, 2015)

theonedub said:


> I literally just finished soldering together 2 molex to PCIe 6-pin adapters into one dual molex to dual PCIe 6-pin and I goofed the wiring. I went to test continuity with my dvm and got nothing. Turns out I wired one PCIe cables 12v (Pin1) to the other PCIe cables 12v (Pin3) then sent that to Pin1 on a molex cable. I repeated that mistake for every wire. The right pins still get 12v, ground, and sense- think it will still work?
> 
> /threadjack but hopefully reading this will remind you to double check your wiring before you get to soldering



Could you provide a wiring diagram? I think I know what you're doing, but I want to be sure before giving a definite answer. My initial impression is I'm a little concerned about how much current you're drawing over the 12v molex wire, but its borderline since I don't know what gauge wire you're using or what other devices might be drawing power on that 12v line.

Part of the assumption of theose dual molex to single PCIE 6 pin is that the total path resistance is really low between the VGA and PSU thanks to all those ground lines so you can get away with (2x) 12v lines powering (3x) 12v connectors.


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