Adding a PCIe Connector to a Power Supply

The first thing I want to say about this post is that in 90% of cases this is NOT something that I recommend. Normally power supplies that do not have a PCIe 6-pin connector lack one for a GOOD REASON. They are not capable of supplying adequate power to a modern graphics card an they should be replaced. Here’s a short list of the criteria you should consider before doing this mod:

- Brand name power supply with a good reputation (I’m using a Silverstone Strider 400W for example)

- Adequate ratings on the 12V rail(s). (The one I’m using is rated for 14A and 15A on its two 12V rails)

- Warranty. You will be voiding it. Don’t do this to a power supply that is still under warranty

- Safety. If performed wrong, this mod could be very dangerous to your power supply, any computer you plug it into, and your health. You could be shocked, start a fire, etc. Check everything thrice.

- Cables - If you don’t have enough Molex or SATA cables as it is, you won’t be able to do this mod. Actually adding cables to the power supply is outside of the scope of this article. In the case of the 400W power supply I used, it has 3 cables each with 3 molex connectors. I decided to sacrifice one of them to be my new PCIe cable.

The first thing I did was clip the two molex plugs off my molex to PCIe adapter. Then I clipped the molex plug off the power supply leaving as much length as possible.

Then all the wire ends were stripped so that they could be joined together.

Once the wires are stripped, we have to figure out which wires to twist together. The easiest (and safest) way to do this is to use an existing adapter for the mod (which we did. We used a molex to PCIe adapter, and all we’re doing is making it permanent) so that you can match up the wire colours by simply plugging it together. In this photo you can see that black goes to brown/black, and yellow goes to uglier yellow. The red does not go anywhere so we’ll show you what to do with that later.

Here you should spread everything out and check your work (obviously with nothing plugged in…). Do a quick sanity check and make sure that you’re basically recreating the conditions of the original adapter.

It’s always best to solder wires together instead of just twisting them for a cable mod like this. We applied flux and solder to make sure that these won’t come apart. I speak from experience when I say that twisted/taped cables will eventually stop working correctly.

You want to make sure that any cables that are not supposed to connect are covered adequately. I’ve wrapped it in several layers of quality electrician’s tape, ensuring that the end is covered as well as all sides.

Here you can see the three cables that we’re still going to use are wrapped and ready to go

Now in order to make our mod more professional looking we’re going to use some cable sleeving, shrink wrap and zip ties to make this look as close to an original part of the power supply as possible.

So now you can hook up your PCIe graphics card without any unsightly adapters, and you’ve managed to turn a power supply that was only useful for low end systems (no graphics) to one that can take on a solid mid-range system again.

I’d just like to re-emphasize that it’s very important to test to make sure the power supply is good enough in the first place, so checking the amperages on the rails is a good way to do that, but another thing you can do is just use the adapter, power up the system, run some intensive stress tests, and see if the PSU works to power your graphics card. Yet another great resource is the tech support of your graphics manufacturer. You can read them the specs of the power supply and ask them if it’s enough.

Also I accept no liability if by following these instructions you bork your power supply, motherboard, any other hardware, yourself, your house, your other property, etc. This mod is performed at your own risk and is just there to offer guidance.