How many motherboard PCI-E pins does a GPU actually need?

[FinalSmash64]

I recently bought a GTX 980 Ti. However, there's a problem with it. The pins that plug into the motherboard have a huge chip taken out of them like this.

 

I knew it was damaged going into the purchase, but I couldn't pass up the price even if the card was bricked.

 

Anyway, I have heard that a card doesn't actually need all of its pins to function. I have heard of someone actually removing all but one of the data pins and the card still worked fine.

 

But, as far as I know, all of the data pins are located on the long pin, with the power pins on the short part. I'm 95% sure this card won't work, but I wanted to get some other thoughts on it. Should I even risk plugging it in to my motherboard? Could it break something? Is there any way to possibly repair it? As far as I know aside from that the card is in perfect condition and would be working fine. Just wanted to get some discussion going and I won't be too disappointed if things don't work out. 

 

It is a shame though, such an incredible piece of hardware ruined like that.

[KarathKasun]

You will need to modify the card to get 12v/5v/3.3v from somewhere else.  AFAIK, that small block of pins is power only.

[FinalSmash64]

6 minutes ago, KarathKasun said:

You will need to modify the card to get 12v/5v/3.3v from somewhere else.  AFAIK, that small block of pins is power only.

How would I do that? Would it just draw more power from the PSU at that point?

[KarathKasun]

Just now, FinalSmash64 said:

How would I do that? Would it just draw more power from the PSU at that point?

No, it will use the same amount of power, you will just be getting it from a PSU cable rather than from the motherboard.

[Alex Atkin UK]

Looks like its going to be more complicated than that as SMBUS, "Hot plug presence detect" and JTAG2, JTAG3 appear to be missing.  Not sure if all those are used, pretty sure SMBUS is as you can probe various GPU statistics via that on Linux.

http://pinouts.ru/Slots/pci_express_pinout.shtml

[KarathKasun]

AFAIK you can get away without having SMBUS connected.  If it is a problem, you can always get a PCIe X16 riser cable and patch those pins through directly using wires.

[FinalSmash64]

6 minutes ago, KarathKasun said:

AFAIK you can get away without having SMBUS connected.  If it is a problem, you can always get a PCIe X16 riser cable and patch those pins through directly using wires.

Okay, so what would be the first step? How do I make it draw the power from the PSU instead of the pins?

[KarathKasun]

Find all the voltage planes on the board where the edge connector used to be, solder some hefty wires to the 12v plane and connect that to 12v on the PSU (do not use small wires, needs to support ~5 amps), do the same for 3.3v (single wire should be fine here).  Make connections on the GPU board somewhere, not at the edge connector.  Make sure none of the pins left can move, plug it into your board, try to power it up.

[FinalSmash64]

8 minutes ago, KarathKasun said:

Find all the voltage planes on the board where the edge connector used to be, solder some hefty wires to the 12v plane and connect that to 12v on the PSU (do not use small wires, needs to support ~5 amps), do the same for 3.3v (single wire should be fine here).  Make connections on the GPU board somewhere, not at the edge connector.  Make sure none of the pins left can move, plug it into your board, try to power it up.

I think that's a bit beyond my skills as an electrician.  That is really cool that it's possible though, I would have never guessed it.

[KarathKasun]

Check out Buildzoids Youtube channel, 'Actually Hardcore Overclocking'.  He was sent a 1080 Ti that had similar damage from a water leak in a custom loop.  He isolated the damaged power plane and wired power around that damage.  The card has been further modified for LN2 overclocking, and lives on for extreme cooling benchmarking.

[FinalSmash64]

4 minutes ago, KarathKasun said:

Check out Buildzoids Youtube channel, 'Actually Hardcore Overclocking'.  He was sent a 1080 Ti that had similar damage from a water leak in a custom loop.  He isolated the damaged power plane and wired power around that damage.  The card has been further modified for LN2 overclocking, and lives on for extreme cooling benchmarking.

lol I've had that video in my recommended feed for the past week, what a coincidence.

[Alex Atkin UK]

18 hours ago, KarathKasun said:

Find all the voltage planes on the board where the edge connector used to be, solder some hefty wires to the 12v plane and connect that to 12v on the PSU (do not use small wires, needs to support ~5 amps), do the same for 3.3v (single wire should be fine here).  Make connections on the GPU board somewhere, not at the edge connector.  Make sure none of the pins left can move, plug it into your board, try to power it up.

I wouldn't touch 3.3v as those connectors still seem to be there.

 

Also as I understand it, the 12v would have to connect to the same place as those connectors did as GPUs have hard limits in their BIOS for how much they can pull from PCIe and how much comes from the PCIe connector.  So if it sees no voltage on the PCIe rail I would expect it to fail to power up at all.

[KarathKasun]

2 hours ago, Alex Atkin UK said:

I wouldn't touch 3.3v as those connectors still seem to be there.

 

Also as I understand it, the 12v would have to connect to the same place as those connectors did as GPUs have hard limits in their BIOS for how much they can pull from PCIe and how much comes from the PCIe connector.  So if it sees no voltage on the PCIe rail I would expect it to fail to power up at all.

It doesnt have to come from the same place, it just needs to connect to the 12v plane that was connected to the slot.  This is easy enough as there is usually a massive chunk of copper right around the slot that should be connected to those pins.