Worldwide server shipments and revenues showed single-digit growth last year, with Sun Microsystems posting its first jump in market share based on sales in five years, a market research firm said.

Server shipments increased 8.9% from 2005 to 8.2 million units in 2006, while revenues rose 2% to $52.7 billion. Mainframes had the strongest revenue growth of any segment for the year, increasing 3.9% over 2005.

The rise in mainframe sales benefited IBM, which continued to lead the overall market based on revenue. IBM increased sales by 1.7% to $16.9 billion. Driving the increase were a 10.3% growth in System z/zSeries, and a 7% increase in System x/xSeries, Gartner said. System p/pSeries and System i/iSeries revenue, however, fell 1.2% and 14.1%, respectively, for the year.

Sun managed to reverse an annual decline in revenue share that started in 2001. The company increased its share to 10.8% from 9.6% in 2005. Revenues in 2006 rose 15.4% to $5.7 billion.

Holding down growth of the overall market was a slowdown in sales of x86 servers. "The fourth quarter of the year exhibited slower growth in x86 servers than we have seen in most recent years," Gartner analyst Jeff Hewitt said in a statement.

The slowdown was due primarily to companies holding out on purchases until the release of quad-core x86 processors, Gartner said. In addition, the increased use of virtualization has led to companies needing less hardware.

The market for RISC-Itanium Unix servers was weak in 2006, Gartner said. Worldwide shipments and revenue fell 1.6% and 0.8%, respectively.

The popularity of blade servers continued to grow in 2006. Revenue jumped 36.5%, and shipments 33% for the year. Blade leader IBM and No. 2 Hewlett-Packard continued to dominate the market. Together, the two companies accounted for almost 74% of global blade server revenue.

In terms of overall server revenue, the top five vendors and their shares were IBM, 32.1%; HP, 27%; Sun, 10.8%; Dell, 10.3%; and Fujitsu/Fujitsu Siemens, 4.8%. Based on shipments, the top vendors were HP, 27.5%; Dell, 21.7%; IBM, 15.7%; Sun, 4.5%; and Fujitsu/Fujitsu Siemens, 3.1%.