Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
MP All Models AMD Radeon RX 6800 XT / 6900 XT for macOS?
- Thread starter Xenobius
- Start date
- Sort by reaction score
Yes, first question to ask is the OS you are running.
For the cMP, meaning 4,1/5,1, the latest OS to support the Radeon RX 6xxx is Monterey.
I bought this one specifically because its one unit, 28cm long:
Gigabyte - Radeon RX 6900 XT GAMING OC 16GB GV-R69XTGAMING OC-16GD
Sounds Like you are using opencore legacy patcher, you need to remove patches and re install them, as you are most likely running without the proper GPU drivers.
Sorry for the delayed response. I have the gaming model, and not the oc gaming. Hope this provides clarity.
I have a syncretic flashed sapphire reference RX6800 in my mac pro 5,1. In windows the card doesn't play well with the OS, degraded performance in gaming, cards not utilized to its full potential. Trawling the web for answers, there are so many accounts of the same same issue, not a 5,1 issue, even PC magazine reported on the issue. I've tried re flashing it, I've seen it run full power, only to be crippled on next boot, cant get it back. RX5700 runs perfectly fine.
Any one else? Did you find a fix, could try going to W11, maybe the gpu scheduler is working with this card
Any one else? Did you find a fix, could try going to W11, maybe the gpu scheduler is working with this card
WW11 same performance. Quick test if you own a rx6000series gpu in windows in gpuz render test shows low clock frequency and low utilization, btw I have seen it at full throttle on both before, only is defaults to a lower power state on reboot.
Same gpu in my other pc is max frequency and max load at all times.
Same gpu in my other pc is max frequency and max load at all times.
Ive spend more time than i can care to admit trying to figure what triggers it on and off, perhaps i just have, I set screen scale to maximum and its render test is at full throttle!? There's definitely a bug in the AMD driver
those are the only ones I know that fit but just check the dimensions / length of the sonnet as it has no room to spare and check other manufacturers gpu specs. Not sure about flashing with the egpu, probably not though.
Last edited:
MAcPro early 2009. 3.3Ghz Intel Xeon 6 cores 32Gbram. Now on Sonoma 14.7.1, but same experience with Monterey. also:
I'v repatched (from Win) the GPU doing at all the whole process. There is not any more White screen, but:
Once patched, the system performs well, but when installing a Radeon RX6600XT GPU, the cursor moves in jumps and videos, no matter how small or what format, appear with tearing and stuttering. The GPU is Navi32 and has been patched previously using the generic FixRX6x00ROM_012. Any ideas, please?
Don’t believe you have support for RX6600 XT on that macOS in your old Mac Pro - think the drivers are only for newer machines. Think support was only in Monterey.
You may need to use older GPU like RX580.
You may need to use older GPU like RX580.
Once again: Navi/Big Navi just don’t work in the 4,1/5,1 with anything beyond Monterey. As easy as that!
Thanks - any official or empirical max PCIe card length for the 5,1? I’ve read someplace that you have to account for the thickness of the back metal plate where the sockets are, etc so it’s kind of tricky to actually measure it directly…
The danger here is if Apple should take the same route with other types of cards as they did with RX6x000 drivers. It would very much limit the continued use of the CMP by forcing everyone back to Monterey or earlier.
Might be cards like the RX6xxx generation just would not be able to run to their full potential in systems like Sonoma or Sequoia without AVX2 supporting CPUs.
Looks like every story comes to an end some day. But for the moment i'm (still) perfectly fine with Monterey.
That's exactly the reason why I have sold my AMD 6800XT dual slot GPU and got a shiny new Workstation Pro card Vega VII. Not as fast, but very calm and runs great with Sonoma & Sequoia. I don't mind to keep changing GPUs because I just love the tinkering part of it.
That’s exacly what i do! 😎
Ok, i kept the 6800 for my daily driver, running Monterey.
But for my Sequoia-tinkering-toy, a 5,1 Single, i got a Vega 64 Liquid Cooling. Not quite as fast as the VII. But i really like the plain looks of it!
Sounds like you are using opencore legacy patcher, you need to install the KDK package which will install the drivers, Run the post patches again sometimes during OCLP install it gets skipped when doing the OS update download at the same time, but you have to use Monterey with a 6600 it will not work with any later versions of Mac OS.
I bought a MacPro 7.1 and transferred everything from my old cMP 5.1 - the NVMe SSD and GPU W6800 with a modified BIOS. I have a question for the devs:
should I return the original BIOS of the video card instead of modified BIOS by syncretic?
because when I launched the AMD diagnostics on windows - it gave an error - it wrote that the hardware is not recognized - not the original AMD, but nevertheless, the radeon pro drivers are installed and the modified card is recognized correctly
And the other question is apple bootscreen with non flashed stock amd gpu avalable to provide boot option (recovery or windows)
should I return the original BIOS of the video card instead of modified BIOS by syncretic?
because when I launched the AMD diagnostics on windows - it gave an error - it wrote that the hardware is not recognized - not the original AMD, but nevertheless, the radeon pro drivers are installed and the modified card is recognized correctly
And the other question is apple bootscreen with non flashed stock amd gpu avalable to provide boot option (recovery or windows)
Last edited:
The Mac Pro 7,1 gives you the boot screen with non apple GPUs becuase it's in the T2 chip on the logic board, no more flashing the ROM to get the boot screen. Syncretic's patch was just a small mod so the 5,1 could boot with the card in it, but did not give you the bootscreen. Sometimes AMD Adrenaline spits out this card does not exist error "oops something went wrong" whn trying to update the drive to the latest version, even with my rx6900xt that is stock bioos, if that is the error you are referring to. I can't remember what I had to do to get Adrenalin updated but might have just left the older version as it's been a while since I messed with it but sometimes you just can't update it because of a windows AMD update mismatch, something like that and you have to delete the drivers to get it to update. You can always flash your rom back to the original but I don't think it is the issue.