http://arstechnica.co.uk/gaming/201...-win-for-amd-and-disappointment-for-nvidia/1/
Now we know why Apple went with AMD route for their GPUs. R9 290X is as fast in DirectX 12, that is based on Mantle, on the low-level end, as GTX 980 Ti.
Metal, Vulkan, and every other modern API is based on Mantle. If your games are optimized for it, you get free performance from your GPUs.
That is really astonishing.
EOT.
I seriously doubt that Apple chose AMD over Nvidia this time around just because supposedly the former cards run better on Directx 12 than the latter ones.
I'm sure there were other criteria instead of that. Apple couldn't care less if AMD's run better on Directx 12.