Hey all, i recently upgraded my mac pro 3,1 ,2 x 2.8Ghz 20GB RAM, to high sierra so far without a hitch. I now have decided to upgrade the card I had in there to something a little better, the HD 7970 3gb which I was running in my 5,1 just fine. I installed it and the computer starts to boot and after the progress bar under the apple logo has ticked about 3/4 of the way through i get hung on a gray screen. I've successfully booted into safe mode with the 7970 installed and go to "About This Mac" and it shows the HD 7970 running what seems properly, but i am at a loss of why its not working through a normal boot up. I have also done first aid to the boot drive and it didn't seem to have any affect. I do have two separate power cords plugged into 7970, a 6 pin and 8 pin(the 8 pin i removed from my 5,1 as i knew it worked). I have also put the old card back in, quadro fx 4800, to see if it would boot normally and it still does. Any help would be awesome.
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Mac Pro 3,1 running HD 7970 issue
- Thread starter elwrith
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Apple started to use SSE4.2 with AMD drivers for any AMD GCN1.0 and newer cards with High Sierra, so every HD 7xxx, R9 2xxx, R9 3xxx, RX 4xx, RX 5xx is incompatible with Mac Pro 2008.
MP3,1 Xeons do not have SSE4.2 and no AMD card, starting with HD 7xxx, will work.
You have to change it for a Nvidia GTX 680 (you can flash it yourself).
Single mode don't use AMD drivers, only EFI ones, so it works.
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Thanks! I’m sure if I scoured forums for hours upon hours or days I could have finally found that. Thanks again TSIALEX!!
There is always the exception, such as this happy HD 7970 user.
https://forums.macrumors.com/thread...ted-macs-thread.2048478/page-70#post-25146912
If you use a hacked Sierra driver to force AMD GNC1.0+ cards to work, you have to disable sleep, loose colour accuracy and have a hacked system. Ok, some will accept that and live with it. But his hack died with 10.13.6. You can't use Mojave with Sierra AMD drivers.
So, forget all the hacks and patches that got AMD cards working with High Sierra on Mac Pro 2008. Just get a eVGA GTX 680 and flash yourself. I did that just to use a non-hacked system.