The iconic pizza box servers can't provide the of blades, nor does it offer the levels of memory and CPU power found in larger 2U and 4U form factor servers, Nemertes Research analyst John Burke said Wednesday during Network World's conference in Boston.

That doesn't mean pizza box servers are being thrown by the wayside when it comes to workloads running on non-virtualized servers. But in IT shops that make extensive use of hypervisors, "the 1Us are losing," Burke said. "We expect that will continue."

Nemertes surveys show most customers will not repurpose old servers for virtualization, instead buying new boxes that are more ideal for the partitioning technology. Blades, 2U and 4U servers "will almost completely replace the 1Us over the next few years" as hosts of VMs, he said.

Burke shared several other findings from Nemertes Research benchmark surveys of IT pros from a mix of small, medium and large enterprises. Ninety-three percent of surveyed IT pros are already using virtualization, though not necessarily in production. Nearly four out of five have virtual servers hosting customer-facing applications, while on the whole 38% of workloads are virtualized. About half the IT shops have seen quantifiable benefits from virtualization.