FRAMINGHAM, MA – Factory revenue in the worldwide server market decreased 7.2% year-over-year to $14.2 billion in the fourth quarter of 2011, says International Data Corp.

This was the first quarterly decline in factory revenue in two years, the firm notes. Worldwide server shipments increased 2% to 2.2 million units in the quarter compared with the year-ago period. For full-year 2011, worldwide server revenue increased 5.8% to $52.3 billion year-over-year, while worldwide unit shipments increased 4.2% to 8.3 million units, says IDC.

On a year-over-year basis, all three classes of servers experienced decreased factory revenue totals in the fourth quarter. Volume systems experienced a 2% year-over-year factory revenue decline to $8.8 billion, while midrange revenue decreased 4.6% to $1.8 billion compared to the same period in 2010.

Additionally, high-end system revenue declined 18.4% to $3.7 billion. This is the first time all three server classes have experienced year-over-year declines in revenue since the third quarter of 2009, according to IDC.

IBM held onto the number one spot in the worldwide server systems market, with 36.5% market share in factory revenue for the fourth quarter, as revenue declined 7.6% year-over-year. IBM experienced continued improvement in demand for its power systems, while revenue for its System Z mainframes declined significantly in the quarter.

HP held the number two spot, with 26.4% share for the quarter, as revenue decreased 16.2% compared to the fourth quarter of 2010. HP experienced demand challenges for both its x86-based ProLiant servers and Itanium-based Integrity servers in the quarter.

Dell maintained third place, with 14.8% factory revenue market share. Dell was the only top five server vendor to grow in the fourth quarter, experiencing 9.7% year-over-year revenue growth.

Fourth-ranked Oracle experienced a year-over-year revenue decline of 11.5% to a 5.2% share of market, while Fujitsu, ranked number five, experienced a 10.5% decrease in factory revenue.

Linux server demand was positively impacted by high-performance computing and cloud infrastructure deployments, as hardware revenue improved 2.2% year-over-year to $2.6 billion, says IDC. Linux servers now represent 18.4% of all server revenue, up 1.7 percentage points compared with the fourth quarter of 2010.

Microsoft Windows server demand subsided slightly during the period, as hardware revenue decreased 1.5% year-over-year. Quarterly revenue of $6.5 billion for Windows servers represented 45.8% of overall quarterly factory revenue, up 2.6 points over the prior year's quarter.

Unix servers experienced a revenue decline of 10.7% year-over-year to $3.4 billion, representing 24.2% of quarterly server revenue for the quarter. IBM grew Unix server revenue 2.5% year-over-year and gained 7.9 points of Unix server market share compared with the fourth quarter of 2010.

In anticipation of Intel's Sandy Bridge server launch in the first quarter of this year, growth in the x86 server market slowed somewhat in the prior quarter, declining 1.7% to $9.1 billion worldwide, as unit shipments increased 2.9% to 2.1 million servers. Even with the slowdown, this was still the second highest quarterly revenue ever reported for x86 servers, as the architecture accounted for 64.1% of all server spending. Although HP's x86 factory revenue declined 11.7%, it continued to lead the market with 33.3% revenue share. Dell experienced the sharpest growth and retained second place, securing 23% revenue share – a 2.4 point year-over-year share gain. IBM continues to hold third place with 18.2% revenue share, while Fujitsu and Oracle hold 3.1% and 2.7% share, respectively. As a result of a strong demand throughout the year, worldwide x86 server revenue for 2011 increased 7.7% to $34.4 billion, while worldwide x86 unit shipments increased 3.7% to 8 million units.

The blade market continued to experience growth in the fourth quarter, with factory revenue increasing 8.3% year-over-year, while shipment growth increased 1.7% year-over-year. Overall, bladed servers, including x86, EPIC, and RISC blades, accounted for $2.3 billion in revenues, representing 16.1% of quarterly server market revenue.

IDC data shows that 89.6% of all blade revenue is driven by x86-based blades, which now represent 22.5% of all x86 server revenue. HP maintained the number one spot in the server blade market in the fourth quarter, with 47.4% revenue share, while IBM generated 21.5% revenue share. Cisco and Dell rounded out the top four blade server vendors with 11% and 8.7% factory revenue share, gaining 5.3 and 1.3 points of blade market share, respectively.

Density optimized server demand grew 33.8% year-over-year in the quarter to $458 million, as unit shipments increased 51.5% to 132,876 servers. Density optimized servers now represent 3.2% of all server revenue and 6.1% of all server shipments. Dell maintained the number one spot in the density optimized market with 45.2% revenue share, while HP finished second with 15.5% revenue share.