High Host RAM usage for Win2k8 and Win7 Guests

Hi

I find that with Windows Server 2008 or Windows 7, the host RAM usage is always just under the RAM assigned to those guests.

I.e.

Win2k8-host-1 (4GB assigned) - Host usage 4085MB, Guest 3%

Win2k8-host-2 (4GB assigned) - Host usage 4166MB, Guest 0%

Win2k8-host-3 (4GB assigned) - Host usage 4160MB, Guest 8%

ESX hosts are running U1, 208167.  Guests are also patched to latest including vmware tools updated.  These three VMs are on the same host and have been running (at fresh boot and idle) for over an hour - I would have expected TPS at least to have been able to reduce this 12GB footprint somewhat?

I find the same with Windows 7 guests, the host RAM usage is basically however much RAM is allocated to it.

Surely the host memory usage should be reduced?

Thanks