I haven't tried dx11 before because I played only multiplayer but I decided to try it and Here's my problem, I enable dx11 from the menu, it says that I need to restart game in order it to take effect, I restart the game, look at the settings and it is disabled, dead circle, any ideas?
and yes, I set it on ultra

When I started the game the first time after installing the patch it asked me if I wanted to enable it since I have a DX11 graphics card. What graphics card do you have? It might not be compatible

Good news everyone, it turns out that the game.cfg file that's suppose to be re-generated (yes, it was not read only) didn't and it was set to dx9 so I typed in dx11 and it worked xD