http://bugs.winehq.org/show_bug.cgi?id=27298
--- Comment #27 from DL dredgingthelake@gmail.com 2012-10-26 21:02:44 CDT --- The CPU has more of an effect with wine than it does with games on Windows. It's just the nature of the D3D -> OpenGL conversion, and you should get quite a large performance increase with a better CPU.
That being said, I agree that there is obviously room for optimisation for this game, and for D3D in general, so it makes sense that there should be a bug for it. Not arguing with you at all about that.