Simple to implement feature yet critical is certain user cases.
Business Case: This feature will help sell this software in corporate IT environment.
Deployment of this software on different hardware with the same configuration is close to impossible since each configuration might have different amount of RAM.
Example: Personally I use my system (testing Win8) installed on a portable device (external HD). Often it is successfully used on systems with very different configurations. Only issue is choosing a Cache Size what will be stable in most cases.
Edit: At very least have some API accessible from Autoit or VBS to enable this functionality.