I noticed that my virtual machine test beds, essential for the development of my Windows utilities, were a bit slow on re-use on a machine with sufficient RAM. This was clearly because much of its virtual memory had been paged out. Checking the options in VMWare Workstation, in the second Settings tab, 'Advanced' section there is: "Disable memory page trimming". Doing a quick verification /w the official docs, this is indeed the issue. I don't want memory so aggressively sent back to the host, I want responsive virtual machines.
There are other options to control the paging of VMWare clients, but this is an important one for those who regularly use VMWare Workstation, have lots of RAM, and don't want it aggressively recovered by clients.