In benchmarks, I saw that hd4850 is less than two times more performant than my old hd4670 which has the same directx9 performance than my hd7730m.
If the team of need for speed got 3 times more fps with directx11 than with directx9 then maybe my card could meet the requirements if the game could be used with something better than directx9 (of course there will probably need some work and optimisation).
AFAIK the DC engine supports both DirectX9 and DirectX11.
I imagine that implementing a way to use an other directx would need a lot of work, but since the engine has been written for opengl, why not optimise the opengl part and use the power of the last version of opengl 3
OpenGL implementations on Windows are generally buggier than the equivalent DX version (since most games use DX on Win).
Also implementing support for multiple DirectX versions is roughly the same work as multiple OpenGL versions.
(opengl 3 is compatible with directx10 and directx11 cards and is compatible with xp, unlike directx 10 and 11)
But OpenGL 3.0 does not have the same feature set as DirectX 10/11.
I'd say that OpenGL 3.2 is roughly equivalent to DX10 and OGL4.0 is roughly equivalent as DX11.
So to support DirectX11-level features you have to use OGL 4.0; if the card doesn't support 4.0, you have to use 3.x, so it has to be backwards compatible with older GL versions (which is the same work as implementing DX9 fallback).
