Here is a little something to consider, and I just so happen to discover this by just experimenting.  Which viewing option are you using in your preview?  OpenGL or SreeD?  I discovered in PP2014 with an external Library that switching from SreeD to OpenGL increased memory consumption of the application alone.  On my system, a grand total of approximately 200mb on an empty scene jumped to nearly 245mb switching to from SreeD to OpenGL.  Interesting that a simple switch in feature would cause Poser to demand more memory.