the memory consumed is a sum of memory used total over a period of time. as Jesse had said the best method of gauging memory would be to use the memory values within the Guest OS. You can also look at the Performance tab in the advanced view to monitor memory calls or %ready. It may be that your VM is waiting for resources on that host or cluster depending on your environment. Remember that even though its a machine, it depends on the hosts within that VCenter cluster (if you have a cluster) to provide the necessary resources.
Also do you run Reservations on resources in your environment? Maybe increase the shares to that VM to ensure it gets at least 2GB reserved and see if that makes any difference as a test. If it does then again look at your host to see if there is resource contention going on.