The back-to-school season did little to reverse the slide in worldwide sales of PCs as consumers continue to favor tablets and other smaller devices, according to preliminary third-quarter results from IT research firm Gartner Inc. (IT)

Worldwide PC shipments totaled 80.3 million units in the third quarter, an 8.6% decline from the same period a year ago, Gartner said in a statement.

The dropoff marked the sixth consecutive quarter of declining worldwide shipments and sales were the lowest they’ve been in five years.

“The third quarter is often referred to as the 'back-to-school' quarter for PC sales, and sales this quarter dropped to their lowest volume since 2008,” said Gartner analyst Mikako Kitagawa.

The analyst said consumers are shifting away from PCs to tablets both in mature and emerging markets. “A greater availability of inexpensive Android tablets attracted first-time consumers in emerging markets, and as supplementary devices in mature markets,” he said.

Third-quarter shipments in the U.S. rose 3.5% to 16.1 million, marking the  second consecutive quarter of shipment growth after six quarters of decline. Gartner cited low inventory from the first half of 2013, and the introduction of new models with Intel's (INTC) Haswell chip for the increase.

Kitagawa said the third-quarter results suggest “the U.S. market may have passed the worst declining stage, which started in 2010.”

Gartner’s report said computer makers Hewlett-Packard (HPQ) and Lenovo are vying for the top spot in the global PC market and that the upcoming holiday season “will be a key battlefield for both companies.”

Lenovo accounted for 17.6% of global PC shipments in the third quarter, and HP had 17.1% of shipments, according to Gartner’s preliminary results.

Some relevant points in Gartner’s report included: strong growth in the Americas offset declines in   Lenovo’s Asia/Pacific market, which was marked by weakness in Chinese sales; H-P recorded positive shipment growth in the third quarter for the first time since the first quarter of 2012; Dell's (DELL) PC shipments exceeded growth rate averages across all regions; Acer’s shipments fell 22.6% versus a year ago; Asus saw PC shipments decline 22.5% from a year ago.

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