I am looking for clarification since I am seeing large allocations of RAM on my Mac. I have 16 GB of RAM and recently installed Windows 7 on Parallels. When the machine runs, I see 3.55 GB Free memory and 8.39 GB Inactive memory. I do not want my RAM to be hogged by Windows if I only need it for a small task and am concerned about a slowly running Mac in this case.

Might the huge amount of inactive memory be due to Parallels being run recently? I am not sure if Parallels is the culprit. Moreover, Wired and Active memories show 2 and 2.13 GB, respectively. The total Used memory is 12.54 GB which means the majority (12.54 GB of 16 GB) of RAM is committed now.

This seems too much. How can I diagnose what is exactly eating up my RAM? I have a retina MacBook Pro and the 10.8 release of Mountain Lion. When I launch Parallels, the increase in memory is allocated to "Wired" yet Inactive memory is still 8GB.

Is what I am seeing explainable?