Further speculation has recently surfaced in regards to ATI's upcoming R600 series GPU (their answer to NV's G80). Apparently its been discovered that this monster will in fact natively support Microsoft's upcoming DirectX 10.1 (due sometime during Q2 next yr). Its also been made clear that DX 10.1 will carry a few notable enhancements over that of the embedded DX10 in Windows Vista, such as better multi-core support and an optimized API.
To learn more about DirectX 10.1, check out this article over at EliteBastards.
Before we begin outright, we should remind ourselves briefly as to exactly why the API will be seeing point releases as of DirectX 10. The main reason for this move is the removal of cap (or capability) bits in the API. In the past, cap bits allowed for graphics vendors to basically pick and choose what features their hardware would support (albeit within some fairly strict guidelines to ensure compliancy to particular DirectX and Shader Model revisions). Although this left the likes of NVIDIA and ATI with plenty of room to develop and tout features that the other didn't have, it also had the side effect of creating development Hell for any game developers working on titles, leaving them to sort through a myriad of cap bits for different GPUs and configurations to ensure that they were supporting the right features for the right boards - More often than not, this simply meant that advanced features that only one graphics vendor supported were left out of the vast majority of titles altogether (Truform anyone?). The removal of this labyrinth was one of the main things developers were screaming out for when it came to discussing what was required of DirectX 10, and so it came to pass.