"Lizardo,An R900 server should work for hosting virtual desktops for your wyse thin clients. VMware ESX Server has the capability to host many virtual machines each with their own OS, apps, etc. The R900 is validated with ESX 3.5.With 45 clients, each with 2 GB memory usage on the server you would need apr 90 GB plus a couple of GB for ESX. It might make sense to go ahead and get 128 GB of RAM to have room for expansion.Are you using the VMware Virtual Desktop Manager? When you reference 2 GB each, do you mean the RAM on the thin client or RAM usage on the server? What apps are going to run in the VMs? How much RAM do you plan to assign to each VM? Thanks,Todd"