suryad said:Thanks for the great explanation!
I got another question though. So when Vista ships, it will have both these Direct3D versions correct? Why 2? Is it for backwards compatibility of the Aero interface on older non-Direct3D 10 class hardware?
With Direct3D 9Ex you will have some benefits from the new driver model with older hardware too. This is primary for AERO but games can profit from it too. Currently AERO use always D3D9 EX even if you have a D3D10 GPU.