DirectX 10.1 maintains the overall structure and programming model of DirectX 10, while providing numerous enhancements, according to AMD. The vertex, geometry, and pixel shader instruction sets have been updated to Shader Model 4.1. Advantages of the DirectX 10.1 include global illumination delivering lighting and shadow quality in real-time that matches the ray tracing techniques used in CG films, improved anti-aliasing techniques to clean up distracting shimmering artifacts, and tighter specifications for improved compatibility. The PDF file is available here.
DirectX 10.1 support will be coming to the Windows Vista operating system with the release of a service pack in early 2008. The ATI Radeon HD 3800 series products are expected on the market in the 15th of November.