GPU Grayed Out

Ok so let's get some info in sync. You can see the version of LrC and my iMac operating in my signature displayed in my post. Please share the specific info of the versions you are using. To be sure there have been lots of changes in LrC versions 8 and 9.4 and macOS 10.14.x10.15.6.

Also, post a screen capture of the top part of LrC Preferences> Performance tab. See the screen capture of my system.

You have also mentioned that Photoshop indicates that the Graphics card is fine. I am not sure why this is relevant, Lightroom is a complete stand-alone application and does not require Photoshop to be even installed on your system for it to function. Are you referring to the Plugin Adobe Camera Raw? see the screen capture.

There was a relatively significant change to GPU in LrC 8.4 update which made some Graphics Cards not fully compatible and I believe you may have been affected. See my post in the thread you posted in earlier today the link is posted for easy reference.

https://community.adobe.com/t5/lightroom-classic/gpu-acceleration-processing-first-worked-now-its-grayed-out/td-p/10629146?page=1

Try the following. Close Lightroom. Browse to the Library folder inside your home folder, go to Application Support/Adobe/Camera Raw/GPU/. Delete the Camera Raw GPU config file you find there and the one in the Lightroom CLassic sub folder.

Restart Classic and check the performance tab. Did it revert to being supported in Auto?

I'm sorry, but what does processing raw images have to do with anything in this discussion? That's all I take, and my computer and Lightroom Classic handles the images just fine. But you can spend the next several weeks trying to resolve the issue. I hope you find something that satisfies you. If the GPU is disabled, and you can't find drivers to resolve that, then either replace your graphics card, get a new computer with better graphics, or just don't worry about it.

That's really all I can tell you. With a computer that's five years old, and doesn't have a 4K monitor, it's highly unlikely that you would see any real benefit from having GPU support anyway. My computer is even older than yours, and I get along just fine without any GPU acceleration. You could try checking to see if they are are any updated drivers that might change things, but I suspect not. I don't have GPU support myself so I can't give you any more information.

It just means that the graphics processor isn't  compatible, and is disabled automatically. Don't worry about it. My computer has on board graphics, no graphics card, and it's disabled as well. If your computer is working fine then just keep using it.