Quote Originally Posted by ErwinSchrodinger View Post
To the OP: I play on the Mac Client with an eGPU, and while it doesn't run as nice as it does on Windows, I get enough performance that I'm satisfied with it. I think the only way we'll see improvements is if the 3rd party WINE provider somehow better supports Metal in Mac OS. Maybe if SE decides to rebuild FFXIV in the future, they'll select a platform that has more tools available for making cross platform games where they don't have to rely on a WINE wrapper. Fingers crossed.
As of the version that supports Catalina, I'm pretty sure the macOS version does support Metal instead of being atop OpenGL. It's just taking a somewhat roundabout method to get there. (DirectX goes through DXVK to be translated into Vulkan API calls, the resulting Vulkan calls go through MoltenVK to be translated into Metal API calls, and then Metal is actually executed.) It makes sense, inasmuch as WINE now uses DXVK so that any DirectX software can take advantage of Vulkan, so building the macOS version atop the existing MoltenVK translation layer rather than writing an entire new DirectX-to-Metal translation makes obvious sense.

The shift to that tower of translation layers is seemingly why the client performs (slightly) better on machines with discrete graphics than it used to, but can no longer run properly on anything using integrated Intel Iris Pro graphics; in a (very cursory) examination of the Crossover bottle in action, MoltenVK atop Metal on the Iris Pro GPU seems only able to emulate Vulkan 1.0, while DXVK seems to require Vulkan 1.1 to function properly.