Gartner and IDC released fourth quarter and full-year 2005 worldwide server marketshare data - declaring IBM the #1 overall server vendor in terms of revenue, #1 in blades and, for the first time in nearly a decade, #1 in the $18 billion UNIX market. IBM secured the top spot in 2005, with 31.8 percent of the UNIX market to Hewlett-Packard's 29.8 percent and Sun's 26.2 percent. Sun Microsystems dominated unit shipments with 59 percent. Although the numbers vary, the overall message was the same: lower-end servers based on x86 microprocessors from Intel and Advanced Micro Devices continue to outpace sales of higher-end servers. In the fourth quarter of 2005, Sun's x86 server revenue grew almost 69 percent. Worldwide server shipments jumped 12.7 percent in 2005 while revenues increased 4.5 percent to $51.68 billion as companies turned to lower-end -- and less expensive -- systems for their computing needs, the research firm Gartner Inc. reported. "The most dynamic market remains the x86 server segment," said Jeffrey Hewitt, a research director at Gartner. "These servers continue to be the choice in increasing numbers to meet the needs of more Web users accessing more file types from more access points than ever." High-end servers based on non-x86 chips that run UNIX saw shipments fall 5.3 percent with just a 0.5 percent increase in revenue, Hewitt said. AMD's Opteron processor made significant progress. Servers using AMD's chips accounted for 6 percent of the x86 server market in the fourth quarter of 2004, but a year later increased to 14.3 percent. Itanium systems took a hit in 2005, with North American shipments falling by 6.8 percent and revenue falling by 1.8 percent. Blade server revenue grew 84 percent from $1.15 billion in 2004 to $2.11 billion in 2005. IDC also reported today, Linux servers generated $1.6 billion in quarterly revenue, the fourteenth consecutive quarter of double-digit growth, with year-over-year revenue growth of 20.8%. For the full year, Linux server revenues were $5.7 billion, placing it in third place for the first time from an operating system perspective as customers continued to expand the role of Linux servers.