Consolidating onto fewer physical servers is one of the technology's key benefits, but of Brandeis University in Massachusetts notes that the needs of a virtualized server are quite different than the needs of a server running only one application.

With virtualization increasing CPU utilization to 70%, "that generates a lot more heat," says Turner, director of networks and systems at Brandeis. "If you walk behind the racks of virtualized servers, the heat is just pouring out of those guys. ... We're seeing heat dump into these rooms like never before."

Turner and many other speakers will share their expertise in Boston Wednesday at Network World's , a one-day event occurring in 10 cities this year.

Using VMware and Xen, Brandeis has virtualized nearly all of its servers over the last couple of years, reducing its total number of physical servers from about 120 to less than 30 today. But Turner says his power use has increased on the whole because virtualization has made it easy to spin up many new applications that he didn't run when Brandeis used only physical resources.

Also contributing to the power crunch is Brandeis's use of a high-performance computing cluster and Moore's law of increasing processor speeds. Brandeis has managed growing power needs by increasing the size of uninterruptable power supplies, says Turner, who specified using APC's Symmetra for its scalability.