DirectX 12 Client

[ReiszRie]

From what I have read DX12 is basically DX11 with mantle baked in. Some improvements over 11, but not radically different. Because of this, all DX11 cards are capable of running with DX12. Fermi, Kepler and Maxwell (Nvidia 500 series forward) will be called DX12 ready cards. Since DX11 is on Win7, there is no reason DX12 can't be moved to Win7, but MS does want to push dat Windows H8 point done.

Unlikely, Mantle is a technology from AMD that seeks to replace DirectX by allowing games to directly communicate with the GPU without passing through another layer, DirectX 12 was created in response to Mantle and as such, you can expect it to take a long while, even till now, there has been little information what advantages and improvements DirectX 12 brings to the table and how it would compare with Mantle which has shown to significantly increase performance

[Nekodar]

Unlikely, Mantle is a technology from AMD that seeks to replace DirectX by allowing games to directly communicate with the GPU without passing through another layer, DirectX 12 was created in response to Mantle and as such, you can expect it to take a long while, even till now, there has been little information what advantages and improvements DirectX 12 brings to the table and how it would compare with Mantle which has shown to significantly increase performance

Work on Direct X 12 started 4 years ago according to nVidia.
It's more likely AMD decided to take ideas from the work they were privy to and make their own API for marketing reasons.