MP 7,1 Mac Pro 7,1 2019 and Gigabyte RX 6800 XT Gaming OC (not working)

[szrtk]

Hi folks,

I just got a Gigabyte RX 6800 XT Gaming OC which I understand should work in my Mac Pro 7,1 in a plug-and-play fashion... but it's not working.

I have the correct set of (OWC) cables, and my previous RX Vega 56 was (and is) working with no issues whatsoever.

After a few attempts, I could get no video signal from any of the 6800 XT DP or HDMI ports.
Tried placing it in both PCIe Slot 1 and 3. Same result.

After installing my Vega 56 alongside the 6800 XT, I can see that the 6800 XT doesn't even appear listed in the system report - neither on the PCI or the Graphics/Displays section.

I can see that the LEDs of the 6800 XT turn on, and the fans spin briefly upon switching the Mac on, and then stop.

Any ideas on why this might be happening? Am I missing anything here?

The card was 2nd hand, a great deal on an eBay auction from a well-regarded seller - who swears it was working flawlessly on his PC.

Thanks in advance for your knowledgeable support!

 

[bmoraski]

Which OS are you running ?

 

[flowrider]

You need to be running Big Sur 11.4 or later.

Lou

 

[szrtk]

Thanks for giving it some traction @bmoraski and @flowrider
I’m running the latest Sonoma, 14.5

 

[flowrider]

I'm also running a Gigabyte RX6800XT with the proper cables. I've had mine for close to four years now. Are you sure the card is seated well and the two cables are properly plugging in? The fans should not stop spinning nor should the rotating lights stop.

 

[szrtk]

@flowrider yes those points have been tripled checked during my iterations - from switching between slots 1 and 3 to different combinations between the 4 OWC cables that match the card. It didn’t work in any occasion.

The LEDs don’t turn off though - only the fans. And getting video output was never achieved, nor the card being recognized by the OS.

I’ve been assembling mac hardware for many years, and I tried all tricks in my sleeve to the point where I’m pretty certain that the card is somewhat faulty as this should not be its expected behavior.

I’m sensing that we’re getting to a point where you guys will draw the same conclusion, meaning that I’m better off returning the card, unfortunately.