When working with map documents and large datasets, you may experience a slight decrease in performance in Adobe Illustrator. You may also experience large AI files after saving. This may be due to the number of layers and amount of spatial data being imported by MAPublisher. One possible solution to increase system performance is to buy more RAM, generally 2GB for average users and 4GB or more for power users.
However, there are several great (and free) options to try before buying another stick of RAM. These methods may sound obvious, but are often overlooked.