It's pretty poorly optimized. There are a couple fixes for the stuttering problem that I tried, some command line input on startup. Don't remember it but I'm sure it'll turn up if you google it. It seemed to work pretty well for me.
I'll have to try this.
This seems to be the fix @dystopiax is talking about. I'm going to try it later tonight, as the stuttering is really bad for me also. Will let you duders know how it works out for me.
Thanks duder. EDIT: Tried it and it works! No more stuttery driving for me!