Ben Armstrong posted a new VBscript to verify real consumption of memory for every Microsoft Virtual Server 2005 R2 virtual machine:
When you create a virtual machine under Virtual Server, you configure the amount of memory that you want that virtual machine to believe that it has (say 512mb of RAM).
However, Virtual Server needs to use more than that amount of memory to actually run the virtual machine. Virtual Server also needs memory for itself to run emulated devices and store various information about the virtual machine in.
Unfortunately, because Virtual Server uses a driver (VMM.SYS) to allocate the memory this information is not easily to determine (i.e. it does not show up in task manager)…
Read the whole article at source.