Among other things, one of the big advantages of DirectX 12 is that it's promises huge gains in performance and power efficiency. It's "close to metal" and cuts a lot of overhead.
During this year’s Build Developer Conference, Microsoft talked about its upcoming API, DX12. Microsoft claimed that DX12 has the fastest adoption by titles under development since Direct3D 9. That’s definitely great news for PC gamers – and Microsoft – as DX12 is advertised as the API that will bring huge performance benefits to the PC platform.
As Microsoft’s Principal DirectX Development Lead Max McMulle said that “this [DX12] has been the fastest adoption of the Direct3D API we’ve seen since Direct3D 9” and continued:
“It’s been the fastest adopted API in more than a decade.”