MP 1,1-5,1 AMD video card for Mac Pro with boot screen

[Calab]

I have a mid 2012 Mac Pro that I'm trying to put back into service. I've installed a "patched" version of Catalina 10.15.7. Right now it has an nVidia GTX680 video card, meaning I get no acceleration. I also have this machine dual booting to Linux Mint 22 using reFind. I'm having issues with the nVidia driver under Linux. This machine is connected to a 4K display via HDMI.

I want to replace the nVidia GTX680 with an AMD card so I can avoid using the default framebuffer under Mac OS and avoid the nVidia driver issue in Linux.

What would be the best card to use in this case, keeping in mind...
- I need to see the boot screen when powering up the Mac
- It needs to be compatible with Catalina (and optionally Majove)
- I need to use the HDMI connection
- I want to use the display at 4K

I don't mind flashing the video card BIOS as long as I have decent instructions.

 

[Bigwaff]

It’s complicated. Read GPU upgrade section. Will help you find your way

The Definitive Classic Mac Pro (2006-2012) Upgrade Guide

The largest/most-complete guide to all possible classic Mac Pro upgrades covering OS, Firmware, GPU, CPU, Storage, USB, THunderbolt and Network upgrades.

blog.greggant.com

 

[Macschrauber]

RX580 plus EnableGop https://forums.macrumors.com/thread...-era-imacs-and-mac-pros.2378942/post-31924217

 

[Calab]

RX580 plus EnableGop

Thank you... I actually have a line on an RX560 card. I don't plan on doing any gaming so it should do the job.

I do have one question that you, or someone else, might be able to answer... Regarding the firmwares on TechPowerUp (https://www.techpowerup.com/vgabios/), do you know if these have already been modded for Mac use, or are they simply pre-mod firmwares? They appear to be pre-mod firmwares, but I'm not sure.

 

[Macschrauber]

Thank you... I actually have a line on an RX560 card. I don't plan on doing any gaming so it should do the job.

I do have one question that you, or someone else, might be able to answer... Regarding the firmwares on TechPowerUp (https://www.techpowerup.com/vgabios/), do you know if these have already been modded for Mac use, or are they simply pre-mod firmwares? They appear to be pre-mod firmwares, but I'm not sure.

Sometimes there are modded firmwares, very rarely for Macs, but this should be written in the comments.

As a role of thumb: If OpenCore (LegacyPatcher) delivers a bootscreen (without the optional setting for pre-load gop in OCLP), then EnableGop in the Mac firmware should do.

A bios mod in a GPU (other power tables, clocks, mining setups) breaks GOP validation. And OpenCore (and EnableGop) delivers no boot screen.