Because Zim 9 always operates in the client/server mode, memory operations performed by the client are not affected by what is being done in the server and vice-versa.

When running Zim on Windows in the client side, the local machine is dedicated to the client session; therefore, all resources available can be used solely for Zim. Consequently, memory is not a concern and the administrator can set configuration options to the maximum in order to improve performance.

The configuration options file for the client is the zimconfig.zim (the database configuration file) and the most relevant options are Maximum Forms, Maximum Form Fields, Runtime Buffers and Sort Buffers. These options can be set to their maximum values all the time. Other parameters like Directories, Document Line Length, Maximum Parameters and Parameter Size can be set to a size according to the needs of the application and can be left to their initial and default state, only changed if Zim states an error.

On the other hand, Zim sessions running on Unix will compete for memory and resources with all other Zim sessions and, most important of all, with Zim Server and its shared memory. Therefore, the administrator must balance the needs of Zim Server and the needs of Zim sessions. Thus, for Unix, the options Runtime Buffers and Sort Buffers must be privileged. The other options (as mentioned for Windows, above) can be configured to some values that still allow Zim sessions to run comfortably without expending too much memory. In general, these values are the default ones that can be changed depending the needs of the application.