Worldwide sales of personal computers grew more slowly than expected in the third-quarter according to two industry reports.

According to beancounters at Gartner weak consumer spending in the United States was largely to blame. Gartner said PC units grew 7.6 percent, versus its prediction of 12.7 percent. PC shipments rose 11 percent to 89.7 million units in the July-September period, according to industry tracker IDC. That was below its forecast of 13.5 percent.

It seems that businesses continued to spend as they upgraded aging PCs, tentative consumers resulted in a tepid back-to-school season in the US. The market rebounded in September but it was not enough. IDC said the US experienced 3.8 percent growth, well off its expectation of near 11 percent.

Top vendors Hewlett-Packard, Acer Inc and Dell Inc all turned in below-market performances in the third-quarter, according to IDC. Looking ahead, IDC forecast global PC growth of 7.4 percent in the fourth-quarter. Maker of expensive printer ink HP turned in the weakest performance of the major vendors, hurt by the weak US consumer market and a sales dropoff in the Asia-Pacific region. Second-place Acer's market share slipped to 13 percent, while Dell's dipped to 12.4 percent.