DX11 is not exclusive to Win7. It's available on Vista as well. Just not XP.
I mean to say that will I get any advantage from using DX11 though I have a 4890?? or it dosent matter which version of DirectX I use to play dirt2(between 10 and 11) ??
Then why does reviews I have read of the game suggest that it is DX11? Most of them mention the game will only run in DX9 or DX11 and point out the lack of a DX10 mode.
I feel codemaster did this because if the game supports dx10 they wont be able to show any difference between dx10 and 11....so they stuck to dx9 and 11...besides since the game is AMD biased they would never like the game to use dx10 as their sales of 5xxx series card would be affected...