I'm trying to spec a Windows Server setup for 110 users spread over 16 sites, with about 50 of those being connected between 9-5. My initial spec for this is two HP Proliant ML350 G6 with a Xeon Quad Core 2.4GHz in each, 12GB of RAM in one and 6GB in the other, storage to be provided by NAS. The one with more RAM would run Server 2008 R2 Standard virtualised on ESXI 5, and Exchange 2010, Sharepoint Services 3.0, and possibly BlackBerry Enterprise Server Express. The other one would also be virtualised and run Server 2008 R2 Standard Core as another DC. Is the hardware going to cope with the connections and software load, or will it cause severe performance issues? I know Exchange and SQL Express are quite hungry for processor and RAM so would it be better to split these off into other VMs? Are there any guidelines other than software requirements I can look at? Any advice is greatly appreciated!