For IT managers who want to do more with less -- meaning with fewer servers -- virtualisation and 64-bit technology are a great combination. In a September 2005 report, IDC said Windows Server 2003 Enterprise Edition offered new benefits, "especially in conjunction with next-generation technologies such as [Microsoft's] Virtual Server and the future integration of the Windows Hypervisor."

Eric Foote, leader of the Intel server and security groups at Detroit Medical Center, says 64-bit Windows will be a good platform for VMware's ESX Server, which he is already running for some applications. For Karl Haas, director of Koehler Group's SAP Competency Center, virtualisation and a switch from 32- to 64-bit Windows servers are two main goals for 2006.

Using virtualisation soft-ware on 64-bit servers will allow Haas to quickly start another instance of a crashed application server that will have the same IP address and network name as the failed server. This will reduce the need to manually configure his SAP applications to find the backup server, which would be necessary without virtualisation, he says.

The ability to run the hypervisor (which manages the virtual machines) in 64-bit mode allows a virtualised Windows server to run many more virtual machines, says Gartner analyst John Enck, even if each of the virtual machines runs in 32-bit mode.