In testing prior the release of MCU 2.5.2 the QA team tested adding and profiling over 1000 systems without issues.
If issues are being seen adding and profile large numbers of systems there is an option to increase the amount of memory available to the Java JVM in the MCU that may assist in resolving related issues.
The configuration is in jvmargs.cfg on the MCU system , which is in \Program Files\Quest Software\Management Console for Unix\jvmargs.cfg
See, "JVM memory tuning suggestions" in that file.
There is more information in the MCU administration guide here: