Lukewarm back-to-school sales and consumer interest in the tablet category kept Q3 PC sales below market research company estimates, according to data released this week. Worldwide PC shipments grew to more than 88.3 million units in Q3, a 7.6% increase from Q3 2009, according to preliminary results from Gartner Inc. The results were below Gartner earlier market outlook calling for PC shipments to grow 12.7%. Meanwhile, International Data Corp (IDC) Worldwide Quarterly PC Tracker estimated the global PC market grew 11% year over year in Q3. The growth was nearly 3% below IDC expectations and equated to approximately 89.7 million units. The major growth inhibitor in the third quarter of 2010 was softness in consumer PC demand in the US and Western Europe, said Mikako Kitagawa, principal analyst at Gartner, in a statement. The third quarter historically is a strong consumer quarter, led by back-to-school sales. Consumer mobile PC demand, driven by low-priced notebooks, including mini-notebooks, slowed after very strong growth the past two years. Kitagawa continued to state that tablets have affected consumer notebook growth by delaying some PC purchases, especially in the US consumer market. The weak back-to-school sales were not because students held off on PC purchases, but because nonstudent buyers, who normally are lured by massive back-to-school promotions, stayed away from PC purchases, she said. These buyers were influenced by media tablet introductions, as well as the still-gloomy economy, since these buyers do not have an immediate need to purchase a PC. Intel in its Q3 report noted similar trends in mature markets. CEO Paul Otellini in the company September quarter call with analysts also assured listeners that Intel does not expect to lose opportunity as tablets gain steam. Instead of a cannibalization effect, he sees new market opportunity and praised Apple for reinventing the category. Apple, IDC said, is not only seeing wins with its tablet sales, but also its Macintosh computer sales, thanks to the iPad. Apple influence on the PC market continues to grow, particularly in the US, as the company iPad has had some negative impact on the mini-notebook market. But the halo effect of the device also helped propel Mac sales and moved the company into the number three position in the US market, said Bob O;Donnell, IDC vice president for clients and displays, in a statement. IDC estimated that the US saw 3.8% PC sales growth compared to a year ago, 7% below forecast. Gartner estimated US year-over-year growth at 2.2% for about 17.6 million units shipped. Q3 PC shipments in EMEA (Europe, Middle East, and Africa) totalled 27.3 million units, an increase of 7.3% from Q3 last year, Gartner said. IDC attributed growth in the region in part to a continued recovery across the emerging markets and increasing business renewals in Western Europe. In Asia/Pacific, PC shipments reached 29.7 million units in Q3, a 10.5% increase from Q3 2009, Gartner said. IDC reported that region came in about 2% below its projections at 13% year-over-year growth, as retail inventory in China and Indonesia impacted notebooks there. Desktops were slightly stronger than expected, but it was not enough to completely offset notebooks, the company said. Latin American PC shipments totalled 8.2 million units in Q3, a 9.9% increase from Q3 2009, according to Gartner data. And PC shipments in Japan surpassed 3.6 million units in Q3, a 14.1% increase from the same period last year, Gartner reported. IDC said that the region showed stronger than expected activity in the enterprise and small- to mid-sized sector. As to vendors, both market research companies named HP as the top OEM in terms of worldwide shipments. Gartner and IDC then each reported Acer, Dell, Lenovo, Asus, and Toshiba respectively among the top six. Gartner preliminary Q3 worldwide PC vendor unit shipment estimates