No image output with a new gfx card

[BillPardon]

I just bought two Gigabyte GV-R9270C-2GD graphics cards (AMD r9-270 cards). I have a working build with a 1000W power supply that previously had an EVGA GTX660SC installed and working fine. I replaced the GTX660SC with one R9-270, connected the two 6-pin power plugs, and fired up the machine. No image output on any monitor. I have a Gigabyte GA-X79-UD5 rev.1 motherboard.

I know what I am doing, but this problem simply baffles me. I have had strange issues with Gigabyte in the past. Does anyone know why I cannot use this graphics card in my computer?

Last time I checked PCI-e is fully forwards and backwards compatible so there should not be any issues using the new cards. Any recommendations?

 

[lonewolf7]

Yes PCI-E is backward and forward compatible so that's not the problem.

Try the GPU on another system to make sure the card is fine. If the card runs fine on another system then you may have to update the MB BIOS with latest version.

And what about the other GPU ? As far as I know 270 requires 1 x 6 pin PCI-E, not 2. Did you make the connections properly, I mean the connectors fitted all the way no loose ends !

 

[mopman411]

I have a similar motherboard and had the same problem when I installed the R9 280X.

Pull out the new card(s), put the old one back in, go into the BIOS and change from UEFI to Legacy. Works like a charm. I can't remember the exact area in the BIOS to find that but its there.

 

[BillPardon]

@mopman411 that solved it. It was under PCI-e video output modes. I would have never guessed at that. I put in a new Gigabyte card and it needs legacy mode. An older card from a different vendor worked with it set to UEFI. Thanks a bunch!