Another trend that softened the overall decline in sales was the Chromebook movement. Powered by Google's browser-based Chrome OS, and made by Samsung, Asus and Lenovo, 175,000 Chromebooks sold during the back-to-school season, said Baker, representing 3.3% of the total of 5.3 million personal computers sold during the period.
"This starts to move the needle for Google," Baker said, "and shows what the opportunities [for Chromebooks] are beyond just at home. It clearly shows some of Google's ambitions going forward."
Most important, said Baker, the Chromebook trend provided a "solid base of competition to the Windows products at the entry-level price points."
Chromebooks should be even more aggressive rivals to Windows PCs in the near future as Acer, Hewlett-Packard and Toshiba launch models equipped with Intel's latest Core i5 processors, dubbed "Haswell," in time for the holidays.
"If you think about the opportunity for low-cost Chromebooks that have touch, what with development and the ecosystem [of Chrome OS] and Android, it'll be interesting to see what happens with Chromebooks and large-screen Android tablets," said Baker, hinting that he thought the two might merge at some point.
"Consumers have been skittish about things that they're not familiar with [like Chromebooks], but Google has spent a lot of money at retail. Most Best Buys have a dedicated person who works that Chromebook end cap, for example," Baker said.
The third platform in the back-to-school sales war, Apple's OS X, also slipped in volume, he said, dropping 3% this year compared to 2012. Mac notebooks accounted for 20.3% of all systems sold during the season.
According to NPD, MacBook ASPs plunged during the summer, falling from $1,445 to $1,286 because customers focused on lower-priced MacBook Airs and MacBook Pros, and because of Apple price cuts in February and additional Best Buy discounts during back-to-school that made starting prices lower than last year.
Both Apple and Microsoft ran back-to-school promotions to juice sales, with the former handing out $100 App Store gift cards and the latter discounting a wide range of PCs and tablets by 10% for college students.
Baker said it was impossible to gauge the effectiveness of the promotions. "You only see a problem if you stopped them," he said. "But no one would have been foolhardy enough to reduce or eliminate them, not in this climate."
NPD estimated that during the back-to-school season, Apple sold 1.08 million MacBook notebooks and Microsoft's OEM partners sold 3.08 million Windows laptops. Approximately 959,000 desktops were sold during the period.
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