... know it's not a big help, but I think it has to be somehting in your configuration or setup that causes this. I have it installed on a desktop and a newer laptop. On the laptop playing is really smooth and I played quite a bit, with and without computer players. Never had any freezing up. The desktop however drove me nuts, because reaction time was slower and the mouse (not the greatest mouse to start with) wasn't reacting too great. it wasn't freezing, but just not as enjoyable as on the laptop.
Perhaps someone in their forum or even support can help on this. Even though it's not included with the offering, but perhaps you get lucky.
Love the game, it's definitely a keeper.