Monterey on 2012 MacPro 5,1 Open Core Legacy Patcher GPU question

[AndyAstbury]

I used to run Catalina on this machine using an unflashed 8GB AMD RX580. The other week Adobe forced all photographers on MacOS to run Big Sur as a minimum.
Because I needed access to my boot picker etc to OCLP this machine to Monterey I installed my old 3GB GTX 780. All is running fine but I really do need to install my 8GB AMD GPU to get my full gpu acceleration and support back.
I tried swapping the GPUs around and the machine gets to the 'loading screen (apple logo)", the load bar gets half way across then the screen goes blank. I get the feeling that the machine is functioning and has booted to the desktop - I just can't see it.
So I swapped the GPUs back again, and the machine works fine - I'm typing this on it.

Is there any way I can get the machine running with my 8Gb AMD RX580?

 

[h9826790]

I used to run Catalina on this machine using an unflashed 8GB AMD RX580. The other week Adobe forced all photographers on MacOS to run Big Sur as a minimum.
Because I needed access to my boot picker etc to OCLP this machine to Monterey I installed my old 3GB GTX 780. All is running fine but I really do need to install my 8GB AMD GPU to get my full gpu acceleration and support back.
I tried swapping the GPUs around and the machine gets to the 'loading screen (apple logo)", the load bar gets half way across then the screen goes blank. I get the feeling that the machine is functioning and has booted to the desktop - I just can't see it.
So I swapped the GPUs back again, and the machine works fine - I'm typing this on it.

Is there any way I can get the machine running with my 8Gb AMD RX580?

There is no need to use the GTX780. Simply keep the RX580 in the cMP and use the OpenCore boot picker (if you really need boot screen).

If you run the patcher with the GTX780 at there, the GPU driver may be patched to fit the GTX780, which cause issues when you swap in the RX580.

Therefore, you better install Monterey with the RX580, but not the GTX780.

AFAIK, the patched system files can be unpatch by using the OCLP apps. You may try to unpatch the system files, then shutdown and swap in the RX580. If that doesn't work, then you better use the RX580 to boot the Monterey installer, and re-install Monterey.

 

[MacHosehead]

Is there any way I can get the machine running with my 8Gb AMD RX580?

Booting with the AMD card in the 2nd video slot worked for me but I don't know why. It seems to be a recent thing.