When working with very large models or a number of diagrams at a time, the modeling tool performance may decrease. To increase efficiency, we suggest the following solutions:
Increase memory allocation value (java heap size). If you want to make sure you have a sufficient amount of memory allocated to your modeling tool, use the memory monitor to track memory usage.
Split a project into several separate project files, and load only the files that you work with. This may help only if your project contains several parts with minimal dependencies between them. For more information, see Project partitioning.