FUD Zilla confirm the next version of DirectX will run on Windows Vista and believes the new API should be available before the launch of Windows 7:
DX11 is based on DirectX 10 but naturally it has more options including Tessellation, compute Shaders - something good for Cuda and GPGPU, CPU multithread support and some new texture compression. Let’s not forget Shader model 5.0 but at this time we don’t know enough about it.
Tessellation might be the most important feature as some developers are getting excited about it. Tessellation can subdivide objects and give them better level of details and more polygons but we don’t know what implementation Microsoft plans for DirectX 11.
The important thing is that despite being designed for Windows 7, DirectX 11 will certainly launch before the new OS and at the same time it should run well on Vista.