Data centers are relying on cheaper chips, thanks to virtualization.

BURLINGAME, Calif. -- It's easy to find an anecdote about a company ditching a big server and buying lots of small servers. Or one about a company replacing lots of little servers with one big one. Call a vendor, and it will find you any tale you want.

But these shifts don't tell the whole story: While the overall market for server computers is recovering, the market for expensive servers running expensive processors is not.

In the last quarter of 2009 server unit sales grew 4.5% over the year-ago-period, according to tech tracker Gartner. Revenue, however, fell 3.2%. That's thanks to rebounding sales of servers built around relatively cheap x86 processors. Intel's ( INTC - news - people ) Xeon and Advanced Micro Devices' ( AMD - news - people ) Opteron server processors are close cousins to the processors powering your notebook and desktop computers, and can run the same software. Unit sales of x86-based servers increased 6.3%. Revenues increased 14.3%.

To be sure, vendors continue to sell many billions of dollars worth of servers built around RISC and Itanium processors every quarter. These versatile, powerful processors can be found in multi-processor monsters and thin, flexible blade computers. Many of these machines will run virtualization software.

Read the entire article from Forbes.com here.