Worldwide shipments of personal computers fell in the third quarter of the year, the sixth straight quarter of decline as cheaper tablet computers and smartphones cut into demand.

That's according to market research firms IDC and Gartner Inc.

IDC said the market fell nearly 8 percent, to 81.6 million units, while Gartner put the decline at almost 9 percent, to 80.3 million.

IDC expects that the PC market will hit bottom sometime next year, with a recovery starting in 2015 as companies finally replace aging PCs.

The U.S. market emerged as a bright spot in both reports. IDC said the U.S. market was almost unchanged, while Gartner said it rose 3.5 percent.

Gartner credited low supplies and Intel's new low-power Haswell line of chips with helping boost demand.