Using oplrun
Explains how to reduce overhead by using oplrun in command line mode.
If you are using the IBM ILOG CPLEX Optimization Studio IDE, consider working with oplrun.
The IDE is very rich and full-featured, but does impose a small, non-trivial overhead in terms of memory usage. If you need only a small amount in memory savings, and do not require the specific IDE features, consider switching to the command-line oplrun executable. It has somewhat lower memory requirements; the savings may help in some limited cases.