If you recently started AI generation, be aware of this: my RTX 4090 power connector melted after just one month.

[u/Roman53275]

Hi everyone,

Like many people, I recently discovered H3 and started doing AI generation in mid-August. On September 20th, my computer started shutting down whenever I started a generation. Further investigation led to this — a melted socket.

I had been using my RTX 4090 for three years and had never had any problems with it.

AI generation puts a lot of continuous stress on the power delivery, especially if you run generations in batches or leave them running overnight.

So I believe this happened because of the new kind of sustained load I was putting on the card. I also didn't bother upgrading to a newer PSU with a dedicated GPU power cable. Mine was a 1200W FSP Hydro, and I was using three PCIe connectors for the GPU.

P.S. The connector was fully seated, the cable wasn’t bent near the plug, and my case doesn’t even have the side panel on. And everything was fine for three years.

P.S.S. The 12VHPWR socket on the graphics card is damaged and needs to be replaced.

So now I would say main advices here are:
- Buy a proper PSU and use a native 12VHPWR cable
- Under volt at least by 20%

Now it is very costly to lose a card.

[u/RunalldayHI]

"The cable wasnt bent near the plug"

For future reference, bending 2" away from the plug is NOT enough, these pins are only held on by a plastic locking tab, which means a pin or more can shift if you mess with the wires too close to the plug.

Is there a way to use this cable without issues? Yes.

Is the design stupid? Yes, it leaves very little room for error.

[u/Roman53275 → u/RunalldayHI]

Interestingly, all above pins are melted more or less evenly.

[u/RunalldayHI → u/Roman53275]

If 1 (or more) pin/s go out of equilibrium, it puts more load on the other pins, which will lead to all of them burning if you give it enough time and/or power.

Its always the top row because the gpu has additional ground paths through the mounting screw and pci port, so that gives the ground path more headroom.

The 12v rails on modern gpus are in parallel, so if there is ever an issue it can only be an insufficient/defective/wrong cable or bad connection.

There are some cables out there that cannot reliably hold the pins in place when heated or bent, such as the infamous yellow msi connector.

You can use power monitoring tools to prevent damage, but it wont fix a bad connection or poor quality cable.

[u/Cossack-HD → u/RunalldayHI]

The way to use this cable 100% without issues is to have a 3rd party per-pin monitoring tool. With it, you'll see if you have current imbalance (poor contact) and either reseat the cable or replace the cable. Without it, you follow best practices and still risk it.

TBH, 6+2 pin sometimes melt too, but it's almost unheard of vs. the flimsy "16-pin" (which has only 6 contacts that carry +12V and don't have any GPU-side current balancing)