Sun Java System Instant Messaging 7 2006Q1 Release Notes

Client Hardware Requirements

Instant Messenger uses between 20 and 40 MB of memory on most platforms. You should estimate the memory requirement by including the requirements of other applications (including operating systems) used on the client machine. In most cases, at least 128 MB RAM is recommended in order to run Instant Messenger and other applications comfortably. This number becomes higher when using memory-intensive operating systems.