@TomF @aras @mcc Also, from my (outside) perspective, it looked like NVIDIA was pouring money into driver optimizations. AMD was getting frustrated that Microsoft was (apparently) completely uninterested in updating DX11, and they couldn't keep up with NVIDIA's "Game Ready" treadmill, so they pushed Mantle (likely intending to donate it from the get-go).

(Roy Taylor saying no DX12 ~5-6 months before Mantle was announced)
megaleecher.net/directx_12