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 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 HP, 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.
HP is stronger in retail sales than Dell, which helped it generate stronger back-to-school sales.
Dell is stronger in sales to businesses, and it could rebound during a corporate PC refresh cycle that could happen in 2010, Chou said. Until then, Dell may struggle to keep up with competitors in unit shipments. The company saw solid growth in emerging markets, IDC noted, which was a positive sign.
Ever since Dell lost its market share lead, founder and CEO Michael Dell has insisted he is more concerned with profits. "If we wanted [market share], we'd go and sell a whole bunch of netbooks," he said in a recent earnings call. Netbooks carry lower profit margins than full-fledged PCs.
Lenovo recorded strong growth of 18.2 percent, giving it the fourth-place spot with PC shipments of 6.99 million. Toshiba was fifth, with shipments growing 6.9 percent to 4.04 million.