Howto: make your own 8pin PCI-E from 8-pin EPS (CPU) connector!

[gamekill]

UPDATE: It has been some days now, and the GTX280 is going rock solid. Even holding up a 24h/day oc to 670/1200... So my GUESS is that the connector mod is pretty safe if done correctly!

I got a GTX280, and my PSU did not have the 8pin PCI-E connector it requires.

I did not have the money to buy a new PSU. And I knew the PSU had 850W and 64Amps on the 12v. So in theory, it had enough power for the GTX280, but not the 8pin PCI-E connector.

But it did have a spare second 12v 8pin CPU connector (for skulltrail mobos etc). Most modern PSUs have this spare 12v connector.

I modded its cables, and the connector so that it would fit into the GTX280.

Guess what it works!!! Been using it for 2 days, Gears of War, Age of Conan, Quake Wars, Lord of the Rings Online, the Witcher, 3DMark Vantage, everything works great. Including the Physx.

So here I am, to tell anyone interested how to do it. It just requires some scissors and tape, and a bit of patience.

PLEASE NOTE, THAT I AM NOT TO BE HELD RESPONSIBLE FOR POSSIBLE DAMAGE TO ANY PARTS INCLUDING THE PSU OR THE GRAPHICS CARD. I'M JUST LETTING YOU KNOW HOW I DID IT.



So, basically, the difference between the PCI-E connector and the EPS connector is: When you are FACING the CPU (EPS) connector (you can directly see the holes), the top pins (5, 6, 7, 8 on the picture above) are the +12v ones, and the four bottom ones (1, 2, 3, 4) are Ground. When you are facing the PCI-E 8pin connector, this is the opposite: The top pins are Ground, and the bottom ones are +12v. BUT THERE IS THE EXCEPTION OF PIN NUMBER 4 (FOUR), IT IS NOT +12v, But it REMAINS A GROUND PIN!!!!!.

So I just cut all the 8 wires and reconnected them, inverting the top ones with the bottom ones, except for the last pair, pins 8 and 4: I connected both these pins to the original cable for pin 4, a Ground cable. And the original wire for Pin remained unused (dont leave it exposed, wrap it with some tape or something).

I made sure I connected all the cables real good and tight, so that they would not be too thick or too thin at the joints. I wrapped electrical tape around each one to "rebuild" them as close to original as I could.

That's it! Working for 48 hours straight now!

[HonestJohn]

Congrats! for walking the fine line between bravery and stupidity, then emerging victorious. +1 Rep for gonads Dude.

Edit 1:

Hey! Where'd the rep button go? Where'd my Reps go, I just hit 20, now they're gone? Figures.

Edit 2:

Just went to the Feedback Forum. Lovely.

[caveman-jim]

sorry.

[HonestJohn]

Originally Posted by caveman-jim

sorry.

That's OK. Now I can let the real HJ out to play and I don't have to worry about getting a negative rep anymore.

[Kowan]

Good job gamekill. Now go to a radio shack and get some shrink tubing instead of tape for those joints.

[acroig]

Originally Posted by HonestJohn

Congrats! for walking the fine line between bravery and stupidity, then emerging victorious. +1 Rep for gonads Dude.

Well said!

[Sweetz]

Could someone with the appropriate electrical knowledge explain why the heck the 8-pin PCIe connector exists?

I looked a wiring diagram much like gamekill did in his other thread about this a few days ago. I was surprised to find that an 8-pin and a 6-pin PCIe connector are exactly the same in terms of the power outputs. The only difference, as shown, is that the 8-pin has two extra grounds. What the heck is the purpose of that, why do you need two extra grounds? Why do you need more than one ground at all for that matter?

[caveman-jim]

for stepping down voltages at different points is my guess, and providing multiple paths for current to flow so as not to push to much down a single wire.

[Sweetz]

Found this page. Looks like it was designed in 1992, but there's lots of good and up to date info there: http://www.playtool.com/pages/psucon...onnectors.html

[caveman-jim]

Originally Posted by Stevedroid

Found this page. Looks like it was designed in 1992, but there's lots of good and update to date info there: http://www.playtool.com/pages/psucon...onnectors.html

Good find! Added to the General Hardware Useful Info sticky

[HonestJohn]

Originally Posted by Stevedroid

Found this page. Looks like it was designed in 1992, but there's lots of good and update to date info there: http://www.playtool.com/pages/psucon...onnectors.html

Excellent reference link Steve, thanks...