Lower FPS than expected

Not a dev but 98.9% sure youre wrong there

 

This game really doesn't demand much from your graphics. It's very CPU heavy. You are probably CPU bound. I get 70-80 fps with just my 670 PE OC, becuase my CPU can handle it

 

this is incorrect, it's 1 car per core (so it would be single threaded) and then tourqe3D has a core for the cpu side of the graphics engine and such

 

I get that, but there's no way that my CPU shouldn't be able to perform good with the specs it has.

 

Did you try pressing J while in-game and then checking the FPS?

 

Take your 670 out and run the game on your HD4000
integrated and post back your results, since it's all your CPU...