Question Motherboard won't detect one of my two cards

[QuintinG]

Hoping someone could tell me what's going on , so I have two GTX 970s paired with the ASUS ROG STRIX Z390-E Gaming and a I5 9600K. One of the GPUs will have no issues in either of the slots. When I swap my second GPU in place, it's not detected in the BIOS at all, no matter if it's PCIE 1 OR 2. I know this card is good because i've had it ran on another setup and it displays video just fine. When I put them in together, most times it'll only detect my card that does display , other times the display won't output until I remove the one that doesn't display anything. I have updated my bios and installed Nvidia driver. Thank you!!

 

[rgd1101]

are you try to do sli?

 

[QuintinG]

are you try to do sli?

I did yes and that's when I saw it wasn't detecting the one. So I swapped them around and it would only see the one that is putting out video , so I tried the one that isn't putting video out alone in each PCIE slot and it's doing nothing but fan twitch a bit , so I went off the onboard video and it doesn't show the card at all in bios as before

 

[QuintinG]

I did yes and that's when I saw it wasn't detecting the one. So I swapped them around and it would only see the one that is putting out video , so I tried the one that isn't putting video out alone in each PCIE slot and it's doing nothing but fan twitch a bit , so I went off the onboard video and it doesn't show the card at all in bios as before

are you try to do sli?

Also I went to a local PC builder /repair to test that GPU and it turns on , fans spin and puts out video HDMI , DVI etc