Hi,
Actually -unless something in Windows changed recently- that is exactly what Windows does on boot.
It intializes the entire RAM on boot and thus it will indeed claim the full amount of RAM that you assigned.
Plus a bit more for if you enabled 3D support etc..
Over time this can be claimed back by Workstation if not used by the guest using techniques such as memory ballooning.
It seems that with Hyper-V dynamic memory you can set startup memory to be used (See Hyper-V Dynamic Memory Overview )
I am not aware of such a feature in VMware Workstation.
--
Wil