Second GPU is not showing up

[KleinRiese]

Hi, I'm new to unraid and would like to use two separate windows 10 VM's at the same time. For that I got a second graphics card (gtx750 1gb). 

My primary GPU is a rx5700xt. 

But here comes my problem. I put in the second GPU and looked into the bios but the gtx750 wasn't showing up. So everything out and just the gtx 750 into the first slot. Tried to boot. Works fine. So card ist mit broken. So everything back to how it was (rx5700xt in first slot and gtx750 in second slot). And I'm back where I started. 

Then I changed my PCIe speed to 4x on all slots and tried booting into windows. And indeed the GPU gets recognised as 'hidden' but I can see it. 

So I bootet back in unraid thinking it's working now but it doesn't. 

Would be great if someone knows a fix. 

 

System is a Ryten 3900x, aorus b550 pro, rx5700xt and gtx750.