Global PC microprocessor shipments increased 31.3% in the fourth calendar quarter of 2009, compared to the same period last year, according to new data from market intelligence firm IDC.

According to the report, mobile PC processors, which include Intel’s Atom processors designed for mininotebooks increased by 11.7% sequentially. x86 server processors grew by 14.1% quarter over quarter while desktop processors grew 4.8% sequentially.

Shane Rau, director of semiconductors: personal computing research at IDC, said: “Compared to 3Q09, the modest rise in shipments in 4Q09 indicates that the market is returning to normal seasonal patterns. Compared to 4Q08, the huge rise in shipments indicates that the market has put the recession behind it. Both comparisons indicate that the PC industry anticipates improvement in PC end demand in 2010.”

In the quarter, Intel earned 80.5% unit market share, a loss of 0.6%, while AMD earned 19.4%, a gain of 0.7%, and VIA Technologies earned 0.2%.

By form factor, Intel earned 87.3% share in the mobile PC processor segment, a loss of 0.7%, AMD finished with a gain of 0.8% with 12.7% and VIA earned 0.1%. In the PC server/workstation processor segment, Intel finished with 89.8% market share, a loss of 0.6% and AMD earned 10.2%, a gain of 0.6%. In the desktop PC processor segment, Intel lost 1.1% with 71.1%, and AMD earned 28.6%, a gain of 1.2%.

For the full year 2009, total PC processor unit shipments grew 2.5%, while revenue declined 7.1% to $28.6bn. Intel earned 79.7% unit market share, a loss of 0.7%; AMD earned 20.1%, a gain of 0.8%; and VIA Technologies earned 0.3%.

IDC has raised its forecast for PC processor unit shipments to 15.1% compared to 2009. Mr Rau, added: “We’re looking forward to the end of the second quarter and the second half of the year as corporations qualify new client and server platforms and open up their IT budgets further. Combined with healthy consumer spending, the resumption of corporation spending will lead to a healthy 2010.”