Essendon wrote: » Windows Server 2008 R2 will need 1GB, a Win7 VM will also need 1GB. So assuming you have Win7 as your host OS: Host = 1.5GB 2008 R2 = 1GB Win7 = 1GB So you should be able to run 3 2008R2 VM's, a Win7 client VM and still leave enough for your host OS. If you had 2008 R2 as your host OS (which I do on my desktop at home), you can squeeze another VM in because 2008R2 only uses about 400MB when idling.