It is most likely because of this bug https://communities.vmware.com/t5/VMware-Workstation-Player/BUG-4GB-Graphic-memory-will-be-reserved-...
Every machine will use more 4GB to the ram for the 3D Graphic support!
If you run 2 machines that is 8 more GB.
Don't expect this bug to be fixed anytime soon, a temporary fix is to disable 3d support but you will get slower machine
