When Windows 10 build 10240 was released on July 29, 2015 It introduced DirectX 12. Microsoft delivered shader model 6 a year later when their Anniversary Edition build 14393 which was released on August 2, 1016. With shader model 6, game developers can now finally start working with the full D3D12 API. Developing new shaders will take some time.

Shader 6 uses a new model called waves. AMD has had something similar with the HD 6970. Our GTX 660 Ti has 7 SMX modules so its already parallel but waves are more abstract. This makes it easier to use 2 or more cards effectively.

Immediately after some existing games were patched to support DX12. This was more marketing than substantive as the games are still fundamentally DX11 class games.