Pc crashes with two gpus

[Panto]

I was thinking of connecting my old gpu(second) to my current computer, sole purpose of mining. While I game and mine(at night) on my main gpu.

So I bought a riser and tried connecting my old gpu, a 7950 card, installed the driver and everything seemed to work fine. Except I get a blue screen, or just simply a black screen after the pc has been running for some minutes. I can usually prowork a crash quicker if I try to use the card, for instance run nicehash.

My main gpu is a nvidia 1080 card and is inserted into the first pcie port, the riser into the second pcie port, I have also tried the 7950 card into the small pcie 3 port with the same issue.

My cables should be fine and the psu strong enough to run both cards, at least idling. My watt consumption while mining with only my 1080 is just under 300 watt, and my psu is 750watt.

Any thoughts on what could be the issue? Faulty riser? Components just not playing nice ?

[HodorHodl]

Could be something as simple as overheating. Are you running them both inside a closed case?

[BitMaxz]

Did you tried to set your fan first to 100% fixed and test if either overheating issue or a driver issue..
Also Did you tried to use MSI burner to overclocked your gpu?
You should also add power connector to gpu 8 or 6 pin cable in the upper side of graphics card..
If its still not working try to change the riser and run your graphics card 1 by 1 for testing and trouble shooting..

[Panto]

Temps are fine. The 1080 is inside my case, 7950 outside.

Both cards have two 6pins connectors attached, 4 total. Not on the same cables connecting to the psu.

It's just a few weeks since I last used my 7950 so both card should be working. Thank you for your inputs.

Really really odd!

What normally happens if the riser is faulty?

Edit: I thought I made some headway. I reassembled everything and used some older amd drivers for my 7950. Everything felt stable, except it did craash after maybe 10 minutes of mining. My screen locked and the temp was around 60 degrees stable on both cards, but when it crashed my 7950 card said 516 degrees on winmer. I mean wtf, that is impossible, it doesn't smell bad either.

The total amount my computer draws is up to 440 watts so my psu of 750 should be able to handle it.

My motherboard is maximus gene V. And for some reason my last and third pcie(mini) slot don't detect my riser so I can't try that slot.

I hate getting stuck like this, my brain wont rest, I need to know what's wrong so I can rest.

Suddenly it just started working. I have no idea why, I kept unplugging and using different drivers back and forth and it just started working. So stupid. Alas my psu makes a lot of noise when both cards are mining so I cba to use them both, even if they only draw roughly 440watt on a 750 psu - should be a decent margin afaik. But the most important part is that it works and I no longer have to spend all time thinking about it.