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 ?