I'm talking about how the game periodically stutters for 5-10 seconds at a time, usually happens once every couple of minutes.

After searching around a lot, most people think it's because the game contacts Ubisofts servers every couple minutes, for whatever reason. I've tried blocking the game with a firewall, but that didn't fix it.

Any help or additional information is greatly appreciated. My specs are:

Windows XP SP3
Intel Core 2 Duo E6600
nVidia Geforce 9800 GTX+
2GB RAM
Realtek HD Audio

Other than the stuttering, the game runs very well and is very stable.