An application that rapidly creates many transient objects will require frequent garbage collections. Increasing the amount of memory in the machine reduces the dependency on swap space and decreases the load on the machine for garbage collections. You should investigate all available hardware configurations and run the application under each configuration. Remember to execute the initial system state steps for each new platform. Analyze the results of each configuration to decide the optimum hardware requirements for your application with its anticipated work load.
Most applications have command line options.
You will want to investigate these options to understand their effect on performance. Run the application with each option. You may also need to run combinations of options. Make only one change at a time before re-evaluating the result, and document each change. Choose the optimal set of options and continue future tuning with those.