Well, since you're on a 32 bit OS, like any 32 bit application it will use no more than 3GB of ram and then start using the hard drive as virtual memory. I would suggest loading only what you need to complete your scene if possible - again, unfamiliar with Victoria's workflow.  It sounds to me like your system may have some memory/hard drive issues and/or a display card that may need upgrading. Manually refreshing your display often shouldn't be needed.  That's not really a Poser issue though, that's more about your system in general.