Worldwide sales of PCs fell sharply in the third quarter, two research firms said Wednesday, as consumers held off for the new version of Windows and spent their electronics dollars on smartphones and tablets instead.

Gartner and IDC said global PC sales fell 8.3 percent and 8.6 percent, respectively.

Gartner also estimates that China's Lenovo Group Ltd. outsold Hewlett-Packard Co. for the first time to become the world's largest seller of PCs, but IDC disagreed and kept HP in the No. 1 spot, though by a narrow margin.

Lenovo vaulted onto the international scene when it bought IBM's PC division in 2005. It's been the No. 2 PC maker in the world for a few years, behind Hewlett-Packard.

Gartner and IDC agreed that Lenovo was the only one of the top four PC makers that saw an increase in sales, thanks to low prices. Dell Inc. of the U.S. and Acer Group of Taiwan are No. 3 and 4.

Microsoft is launching its new operating system, Windows 8, on Oct. 26. It's designed to work better on tablets and PCs with touch screens.

A third research firm, IHS iSuppli, projected Wednesday that PC shipments will fall this year, for the first time since 2001.