LOL, I searched for the term "directx" in the detailed list here:
and found this
MS08-033: Vulnerabilities in DirectX could allow remote code execution"
FIX: You cannot create an AVI file that is larger than approximately 512 GB, and you cannot play back an AVI file that is larger than approximately 800 GB by using DirectX"
So much for DirectX improvements. Still I somehow know the fanboys are gonna scream OMG VistaSP2 my FPS skyrocketed!!111!