Worldwide PC shipments rose 7.3% from a year ago to 64.7 million units in the fourth quarter of 2006, according to IDC's Worldwide Quarterly PC Tracker. This was slightly slower than the past several quarters, and down from more than 15% in 2004 and 2005.

Fourth quarter growth was also a few points behind expectations as slow commercial buying – particularly of Desktops in more mature regions – constrained the market.

Annually, PC shipments reached 227.7 million units with growth of 9.5% and shipment value of US$231.9 billion with growth of 6.1%. Desktop volume of 138.3 million units was up less than 2% over 2005, while Portable shipments of 82.4 million were up 26.3%. While Desktop volume will grow by low single-digit rates throughout the forecast with a compound annual growth rate (CAGR) of 3.8% from 2006 to 2011, Portable PC shipments will maintain a CAGR of 16.1% over the same period. As a result, Portable PCs will represent more than 50% of all Client PCs worldwide in 2011 with a CAGR for Client PC shipments of 9.1%.

The role of emerging markets is also growing. Asia/Pacific (excluding Japan) and Rest of World (including Latin America, Canada, Central and Eastern Europe, the Middle East, and Africa) represented more than 50% of Desktop PC shipments in 2006 and will represent more than 50% of all worldwide PC shipments in 2011.

"Slower growth in Desktops and in relatively mature regions changes the market dynamics a bit," said Loren Loverde, director of IDC’s Worldwide Quarterly PC Tracker. "A strong Portable offering is becoming more important, and while local players have a larger share of international markets, the shift to Portables will favor the largest players. Portables are picking up some of the slack from Desktops and will benefit from improved security, power management, and new designs supported by Vista. While more replacements and Vista adoption may provide a brief respite for Desktops in 2008, essentially all Desktop growth will occur in emerging regions."

"In the United States, portable PC shipments will maintain double-digit growth through 2010, but this shift to mobility will not be enough to offset reduced demand for desktops," said Doug Bell, analyst in IDC's Personal Computing program. "The outlook is valid for both consumer and commercial segments, creating mid-single digit growth for the entire market, peaking in 2008. However, the release of Vista and a desktop refresh will create some growth opportunity in late 2007 and early 2008, before resuming a declining growth trend in the out-years."