P870KM1-G issue with second GPU slot and SLI

Hi, I had a P870KM1-G that I had bought a while ago to replace my now dead P870DM2. specifically earlier this year. Also it came with a bios mod (dsanke's bios mod i believe) so I could use my i9-9900K in it. which it works great as far as the i9. However I have found a bit of a issue with it lately. I have two GTX 1070 MXM cards, both of them G-sync cards, however no matter what I do, I can't get the 2nd one to show up at all. Not in the device manager nor anything. Despite this with all the cables connected, the 2nd GPU still warms up. and the 2nd gpu fan works. I was hoping to have a SLI setup with both 1070s

I tried:

• Two different SLI Cables, one which was originally for my DM2, and one specifically for the KM model. Nothing popped up in either OS I had on it (dual booting W7 and W10)

• Tried it without the SLI cable, still nothing popped up. only GPU1 seems to work.

• Made sure that it wasn't an issue with the VGA2 power cable, clearly the cable is working fine, otherwise it would shut off after two seconds.

So I'm at a loss here, what exactly is going on here. a bit disappointed i can't get both 1070s to work together.

 

I think this is a BIOS bug, and you have to make sure you did the CPU mod (isolated/shorted) pins with the right way.

 

Maybe the second 1070 needs a vBIOS update.

 

Both cards needs the same special vBIOS,

 

Just don’t flash that one if you’re the OP, because that’s a 1080 vBIOS.

 

The sli cable won't affect whether the gpu shows up in device manager. Don't waste time troubleshooting that (only if the sli option doesn't appear in nv control panel but that's after it's working fine).

Have you reseated the card in the slot?

Other than that, yes look at vbios

 

Yes, you are right, don't flash that one for 1080, you have to find the 1-70 one.

 

The BIOS mod/pin mod was already done. I checked to see if the pins were done correctly and the two specific pins were properly isolated. so the CPU portion seems to be fine.

I had indeed already flashed a vbios to it, in fact to make sure, they both have the same vbios.
The vbios i had flashed on both was "86.04.2A.00.29" which is supposed to be the sli compatible 1070 gsync vbios. Unless there is a different one i am supposed to use.

I checked multiple times, the card is properly in its slot. so yes its in there, so i'm assuming its something with the vbios.

 

Tried swapping the GPUs? It could be dead.

 

Okay I just checked the other card, swapped both of them, and its doing the same thing. so basically both GPUs alone work fine, but for some reason neither GPU is showing up, even swapping them.

 

BIOS/VBIOS related issue then most likely.

 

I'm assuming as much, it has to be one of the two. I already flashed the vbios on both of the 1070s with the 86.04.2A.00.29 vbios from this thread here, so unless the problem is a newer vbios for the 1070 im not aware of.

 

Just to confirm only one card is showing in device manager?

 

That is correct. only one card shows up, that being the 1070 in the first slot.

PS: I just tried basically putting another card in the 2nd slot, this one being a GTX 980M despite being a different card. that one also did not show up in the device manager. even checking NVflash's list option, it only shows one card instead of two. It's seems like the 2nd card slot is still functional since the card gets warm, so i'm starting to think it might be something with the modded bios.

 

Let's ask the obvious: how's the SLi connection?

 

Both cards should still show in the device manager, it could be getting power to slot but some of the pins might be bad. Have you looked at the pins in the slot?

 

I checked each pin in the GPU slot and it looks good, no dust, or any bad pins were present.

UPDATE 9/9: I figured out the problem, The bios that was flashed on it by the guy I bought it from was meant for the P75x/P775 models. I took a gamble and flashed the 9th gen bios myself for the P870KM and after making sure everything went alright. I put the 2nd 1070 in and it works! Problem solved!


Now it's fully functional! SLI works and everything.

 

Wow, he could have easily bricked it. Well was a bios issue then.