The DesignTools Memory Monitor is a deceptively simple looking program but under the hood there is some very interesting code running. The first version of the Memeory Monitor was written in a night to solve an immediate memory leak problem in one of the SPB 15.x versions of the Cadence PCB Editor (Allegro). The memory leak would eventually take up all of the system memory and hard crash the system, losing valuable design work.
Since the designers I know *needed* to keep working and doing a down-rev of the Cadence tools was not an option, I wrote the Memory Monitor to warn them when Allegro memory usage reached a particular limit.
If your system has 2GB of RAM but you're running many programs besides Allegro, you can set your "System" memory lower in the Memory Monitor and then click the "Reset" button to apply the new value.
The Memory Monitor will warn you when Allegro uses 80% of the memory limit you set in the "System" field.