Global PC shipments will rise by 16.7 per cent in the fourth quarter of 2007 driven by strong demand for laptops and portable computers, according to IDC's latest Worldwide Quarterly PC Tracker.

The report noted that, following a slow second half of 2006, growth has accelerated steadily in 2007, reaching 16 per cent in the third quarter.

As a result, annual growth is expected to reach 14.6 per cent in 2007, up from 10.1 per cent in 2006.

Portable PC adoption remains a key driver. Worldwide portable PC shipment growth of 37 per cent in the third quarter was the fastest in more than a decade, beating growth of more than 35 per cent in several quarters in 2003 and 2005.

This rapid move to portables has taken a toll on desktops, the study revealed. With the support of emerging regions, global desktop volumes continue to increase in low single-digits.

However, the growth differential between desktops and portables has never been greater. In the third quarter, portable growth was more than 33 per cent faster than desktop growth, a differential that has not been over 30 per cent since 1996.

"The peak portable growth seen in the third quarter will be difficult to sustain, but it reflects strong demand across regions and segments that will fuel growth," said Loren Loverde, director of IDC's Worldwide Quarterly PC Tracker.

"It will be increasingly important for PC vendors to have a strong portable offering to stay competitive as the market continues its rapid shift to mobile computing."

International markets have also driven volume. Following years of steady growth, the PC market outside the US and Japan reached 68 per cent of global shipments in the third quarter.

Asia/Pacific (excluding Japan) and Rest of World (including Latin America, Canada, Central and Eastern Europe, Middle East and Africa) are approaching 50 per cent share and grew by more than 20 per cent in 2007.

Western Europe, representing more than 22 per cent of global volume, also continues to grow at a rapid pace.

"The significant influences driving the growth of portable PC volume include falling prices, the narrowing performance gap as compared with desktops, improving wireless connectivity, and the expanded access through retail channels," said Richard Shim, personal computing research manager at IDC.

"The desktop market will aim to maintain share by emphasising improvements in energy efficiency, shrinking case designs and emerging mainstream opportunities, such as gaming and all in one systems."