This has been bothering me for quite some time, and I still haven't found a solution. Hoping I can, this time. I have made the switch to Apple since 2020 (with my first 2019 model MacBook Pro, followed by a 2020 model high spec iMac...with a 16GB 5700XT GPU). I have noticed that using the GPU on a Mac is greyed out in the Preferences, and Substance Painter only uses the CPU to bake maps. Needless to say, this is extremely time consuming, and can take over an hour for a 4K, multi-light rays bake. I have a Windows PC alongside my Mac, and there are no problems there, with bakes taking a few minutes using the same bake settings using the GPU (2080ti).
Is there ANY way possible to enable the GPU to bake my maps on my iMac??
I would rather try to avoid dropboxing my SP files between the Mac and Windows for my bakes.