Worldwide server shipments increased 12.8 per cent during the second quarter, compared to the same quarter last year to reach two million units, according to statistics released by Gartner.

During the same period, worldwide server revenue climbed 2.5 per cent to $12.4bn for the quarter.

"The two server categories that exhibited the greatest strengths were x86 and blade servers," said Jeffrey Hewitt, research director at Gartner.

"X86 servers and x86 blade servers continue to be the systems of choice for growing the front and middle tiers of the web infrastructure.

"RISC-Itanium Unix servers grew 1.8 per cent in shipments for the quarter but dropped a more significant 2.6 per cent in revenue.

"This segment continues to be hotly contested on a global basis, but suffered from constrained revenue overall in the second quarter."

IBM continued to lead the worldwide server market based on revenue, with its System x/x Series and System z/z Series growing during the second quarter of 2006.

But the firm experienced declines in System i/i Series and System p/p Series which resulted in a slight overall revenue decline of 1.7 per cent.

IBM retained its overall blade server lead in revenue and shipments as its blade server shipments increased 45.4 per cent in the quarter.

In server shipments, HP dropped 0.1 per cent in share, but retained its worldwide server shipment lead and extended the share gap between it and second-place Dell by just over two percentage points.

HP's year-over-year shipment growth was 12.5 per cent in total, with ProLiant and Integrity product lines increasing 13.4 per cent and 7.9 per cent respectively, while HP's remaining server brands fell for the period.

These shipment dynamics dragged HP's overall revenue down 3.8 per cent for the period.

Sun Microsystems posted significant annual growth in shipments and revenue.