Mac Pro 4.1-5.1 Catalina 10.15.7 GTX680 DisplayPort not working

[abcd-abcd]

I used DosDude1's software very successfully to update my Mac Pro 4.1-5.1 from Mojave to Catalina 10.15.7 which runs perfectly, although I have just found out that the DisplayPort on the GTX680 does not work (as I want 4k/60Hz). This is a known problem, though I cannot find a solution. Does anyone know how to fix it please? (hopefully without having to change anything else!). Thanks very much.

 

[joevt]

At least one person says DisplayPort can work from a GTX 680 with Catalina but I haven't tried very hard to get it to work myself.
https://forums.macrumors.com/thread...lina-led-cinema-display.2298246/post-29950160
I suspect a solution might involve OpenCore/WhateverGreen/Lilu.

 

[joevt]

Actually, I found a possible solution at https://github.com/mayankk2308/purge-wrangler/issues/48

I got DisplayPort working on my EVGA Nvidia GTX 680 Mac Edition in Catalina by modifying /System/Library/Extensions/AppleGraphicsControl.kext/Contents/PlugIns/AppleGraphicsDevicePolicy.kext/Contents/Info.plist

Duplicate the file to your home folder, add your board-id as key and none as string, save, then replace the old file with the new file and sudo touch /System/Library/Extensions

 

[abcd-abcd]

Thanks very much #joevt - I will investigate...

 

[abcd-abcd]

#joevt - I tried to do this, but was unable to replace the old graphics plist with the new one, because it was locked and I didn't have the permission to unlock it... any ideas? Thank you.

 

[joevt]

#joevt - I tried to do this, but was unable to replace the old graphics plist with the new one, because it was locked and I didn't have the permission to unlock it... any ideas?

For Catalina, you need to mount the system volume as read write. I don't know what to do for Big Sur.
https://forums.macrumors.com/threads/gpu-compatibility-list-for-cmp.2174600/post-30209358

 

[abcd-abcd]

Hello all - my GTX680 DisplayPort still does not work. I am using Martin Lo's Opencore for Classic Mac Pro 0.7.4 with Big Sur 11.2.3 - do you think it's worth me upgrading to Big Sur 11.6 now that it 'should be ok' ?! Do you think the upgrade might bring back the DisplayPort? And how do I roll back to 11.2.3 if it messes something up? Thanks.