MP 1,1-5,1 MacPro 3.1 with Catalina and RX580 + 8800GT (revert legacy video patch)

[Fulberti Enzo]

Hi to all,
I recently bought an old MP3.1 dual Xeon 2.8 Ghz with 12Gb Ram and 8800GT video card and it came with El Capitan. I managed to upgrade it to Catalina using Dosdude's patch and used the legacy video patch to get some degree of hw acceleration from my graphics card but now I got my hands on an retail RX580 and wanted to upgrade my Mac with it but can't get it to run (but strangely it works if I boot again the usb I used to install Catalina on my Mac....I mean I kept my 8800GT and added the RX580 on the other pcie x16 so I have boot screen). In the installed Catalina all I get is my 8800GT and on the second PCIEx the os sees my RX580 card as "monitor". I guess that installing the legacy patch I lost the drivers for my RX580 (that is supposed to be supported by Catalina). Is there a way to have both cards working (even if I loose the HW acceleration on my 8800GT) or at least get the rx580 fully supported even tho loosing boot menu graphics...
Thank you all

 

[KeesMacPro]

Generally speaking it's not recommended to install Nvidia and AMD GPUs together, it can lead to all kinds of issues.
To get your RX 580 working:

MP3,1 (& others?) SSE 4.2 emulation (to enable AMD Metal driver)

MouSSE (Partial SSE4.2 Emulator) Public Release Current version: 0.95 (8 Jun 2021) When referring folks to MouSSE, please just link directly to this post, which will always contain the latest version & info. EDIT (8 Jun 2021/1 Sep 2021): Monterey changed things up, so a new version was...

forums.macrumors.com

 

[Macschrauber]

To get ridd of the legacy video drivers install the OS again over it and reapply the patches.

With legacy Graphics off

 

[Fulberti Enzo]

Generally speaking it's not recommended to install Nvidia and AMD GPUs together, it can lead to all kinds of issues.
To get your RX 580 working:

MP3,1 (& others?) SSE 4.2 emulation (to enable AMD Metal driver)

MouSSE (Partial SSE4.2 Emulator) Public Release Current version: 0.95 (8 Jun 2021) When referring folks to MouSSE, please just link directly to this post, which will always contain the latest version & info. EDIT (8 Jun 2021/1 Sep 2021): Monterey changed things up, so a new version was...

forums.macrumors.com

Already done that...as I have dosdude's patch....but still doesn't get recognised
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[KeesMacPro]

Did you try without the 8800gt?
So only the rx 580 installed?

 

[Fulberti Enzo]

Did you try without the 8800gt?
So only the rx 580 installed?

Yes and all I get is "no signal" for 30 minutes and then my monitor just power's off

 

[Macschrauber]

You must get the driver working, first

 

[Fulberti Enzo]

You must get the driver working, first

And how am I supposed to do that ?

 

[Macschrauber]

MacPro 3.1 with Catalina and RX580 + 8800GT (revert legacy video patch)

To get ridd of the legacy video drivers install the OS again over it and reapply the patches. With legacy Graphics off :-)

forums.macrumors.com

Plus apply the sse4.2 patch
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You cant have legacy and non legacy drivers in your system setup at the same installation.

Since high sierra you also cant mix nvidia and AMD gpus.

So you have a dual situation what will not run.

1st gpu vendors mix
2nd legacy and non legacy drivers

Even a 3rd problematic situation: the amd driver needs SSE 4.2 - but this is fixable with adding an extra patch.

 

[Fulberti Enzo]

So to make it brief what I have to do is:

1. Install Catalina with 8800GT using the installer I created using dosdude's patcher, without installing the legacy video drivers, but apply sse 4.2 patch.

2. Shutdown MP once I have all setup and replace the gpu with RX580 and start sistem without boot image and wait until I get in osx ?

 

[Macschrauber]

Yep,

For bootscreen and other useful things checkout opencore.

 

[fredd3]

So Enzo, can we assume this was successful. Sorry to bring up an old thread, but I'm experiencing a similar issue with a cMP3,1 & MSI RX-560 AERO 2GB in Catalina.

 

[fredd3]

No reply from Enzo, but I can verify that the re-install without the legacy GPU patch worked for me. The RX560 is working and all the available sound options are there(headphone, digital in/out, monitor) including sound through the HDMI.