Global PC shipments grew 2.3 percent from the same quarter a year earlier, to 78.1 million units. It was the first quarter this year in which PC shipments have grown, IDC said.

Acer's shipments grew by a whopping 25.6 percent to reach 10.96 million units, outpacing Dell, whose shipments declined 8.4 percent to 9.95 million units. Acer "outperformed the market in virtually all regions," IDC said.

Acer benefited from strong shipments during the back-to-school season, as prices for laptops fell and netbook shipments gained momentum, said Jay Chou, research manager at IDC.

Dell has not embraced low-cost netbooks as enthusiastically as Acer, Chou said. Acer benefitted more from the competitive pricing environment for laptops and netbooks.

Acer ended the quarter with 14 percent of the market, compared to Dell's 12.7 percent. Both companies trailed Hewlett-Packard, which retained its spot as the world's top PC vendor. HP held 20.2 percent of the market after shipping 15.79 million PCs, a year-over-year growth rate of 9.3 percent.