To suggest it is merely lack of drivers is an oversimplification. There is a chip errata that prevents PCIe GPUs from working properly on Apple Silicon: the architectures are not compatible. Apple Silicon GPU drivers are deeply integrated into the system. Due to this integration, only graphics cards that use the same GPU architecture as Apple Silicon could be supported, and there just aren't any, and I don't see how there could be unless Apple developed one and released it.
> To suggest it is merely lack of drivers is an oversimplification.
Not really. When you hook up an external PCI chassis with a graphics card inserted, it sees the PCI expansion slot and the GPU just fine, it just doesn't have a driver for the GPU.
Not really. Software drivers alone will not get it done, at least not adequately (Asahi-related developers may come up with a software solution for Asahi, but it will necessarily degrade performance, so the effort is likely to be abandoned).
Thunderbolt supports PCIe, and for most devices Apple Silicon does also, but GPU is different enough from audio interfaces and NVMe that it isn't just a "load the driver and plug it in" situation. GPU is vastly more complex than other PCIe devices. Apple Silicon and x86 architectures are not compatible, so GPU for x86 is not going to work with Apple Silicon with merely a software driver.
It's going to take hw translation and other technology that is not yet available for Apple Silicon, thus Apple's recent patent applications,[1] showing that Apple is either exploring supporting outboard GPU or locking anyone else out from their method of doing so, but either way is no guarantee they'll complete development or release, because it seems just as if not more likely the roadmap for Apple Silicon GPU performance will outpace nVidia and AMD GPUs.
But, again, claiming, "it just doesn't have a driver for the GPU" is a staggering oversimplification.
