Poor in comparison to the 770. If you can't see how different that delta is compared to how well the Titan X is supposed to run in comparison to the 770 then...what am I saying...of course you can't see the issue here. I wasted one year trying to tell you. Haha....facepalm.
Okay, so just to be clear, you're complaining that Metal performance isn't as good as DirectX under Windows? I've spent a year trying to explain to you what it means to be CPU limited, and how the Apple OpenGL framework makes it impossible to match Windows OpenGL or DirectX performance, so I'm hoping we're past that.
Let's look at how the original 3.0 version of Manhattan performs. D3D gets 735.5 FPS, Metal gets 625.2 FPS, or about 15% slower. Is your whole argument that Metal should match D3D on a test that renders more than 10 frames every screen refresh? Given that NVIDIA has more people working on D3D performance than they have working on all aspects of the Mac drivers, it's not surprising that they've been able to squeeze out more performance here, and/or that their Mac team has been focusing their effort elsewhere.
Let's look at how the 3.1 version of Manhattan performs. Metal gets 423.8 FPS and beats Windows OpenGL with 345.3 (though the max score looks like it's much closer). What are you complaining about here, exactly?
So, what exactly would make you happy with respect to GFXBench results? Are you upset that GFXBench isn't matching what you expect based on the paper specs of the two GPUs? What makes you conclude that the Mac driver is running in compatibility mode, or doesn't have color compression enabled? I get that you think the NVIDIA web drivers are **** and that they should be doing a better job of supporting your usage cases, and you've raised some legitimate concerns about issues with Adobe apps (many/most of which have already been addressed).
Enjoy your Polaris GPU, I'll enjoy using my 1080 Ti when it gets released. I was hoping to be able to include comparisons to the high-end AMD GPUs like the Fury X, but I wasn't able to find any data. So yeah, let's keep complaining about the NVIDIA web drivers because they're at least enabling all their GPUs to work.