Growth will continue at above 11 per cent in 2009 followed by high single-digit growth to 2012, boosting annual shipments to over 426 million.
Overall volume growth, combined with a steady transition to portable PCs, which generally cost more than desktops, will help offset falling average prices.
The total value of PC shipments is projected to grow by 7.4 per cent in 2008 to nearly $280bn. Shipment value will continue to grow by roughly four per cent annually from 2009 to 2012, reaching nearly $330bn.
Portable adoption remains the "primary driver" in all regions, nearly matching record quarterly growth in Q3 2007, and record annual growth in 2005.
Increases of more than 50 per cent in Asia/Pacific (excluding Japan) and Rest of World helped boost these regions to more than 36 per cent of portable volume.
The US and Western Europe saw growth above 20 per cent and continue to account for more than 50 per cent of portable volume.
"The deteriorating economic environment can certainly put a damper on PC growth," said Loren Loverde, director of IDC's Worldwide Quarterly PC Tracker.
"However, fourth-quarter growth was the fastest since mid-2005 and we should see continued portable adoption and PC acquisition by commercial and consumer segments.
"Replacements in mature regions supported by ongoing rapid growth in new users in emerging regions will add to pervasive technology evolution and falling prices to sustain growth."
Bob O'Donnell, vice president for clients and displays at IDC, added: "Lower cost consumer notebooks continue to drive PC market growth in all regions around the world.
"Consumers are increasingly seeing notebooks as essential personal communication and information gathering tools and we expect that will continue to drive growth and higher PC penetration ratios for several years to come."
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