Beh... quella che ho fatto io gira con 768Mb... sarà che
sono parsimonioso sui servizi da usare e installare... 
Comunque quando esce la scarico e vi dico com'è...
The beta 2 Virtual PC image was hugely popular. The new Team Foundation beta 3 VPC image is now making its way up to MSDN. So, later today or Monday you'll be able to download and run a single-server and client beta 3. Just make sure you have plenty of RAM since you'll be running everything on one machine (say 2GB+).
Fonte: Team Foundation Beta 3 Virtual PC is headed your way