Mac Spec's for best rendering

Hi people, i’m using Vray for SketchUp a few months. I use it for professional use (I’m interiorarchitect). My latest projects get more and more complex and my Mac is getting slow I think on rendering images.
Now I was wondering what kind of Mac Pro should I get to render “quickly” (better then on a macbook pro).

Or can I know your mac spec’s.

Thanx !

TDesignS