Global computer shipments will climb less than previously forecast this year amid a weak economy and as buyers await new models, research firms IDC and iSupply say.

Looking into the future, IDC also cut its annual growth rate for PCs from 2013-2016 to 7.1 percent from 8.4 percent.

“The U.S. market will remain depressed until Windows 8 products hit the shelves in the fourth quarter of 2012,” warned David Doud, research director for personal computing at IDC.

“The industry is responding by reducing shipments of PCs and clearing Windows 7-based inventories to pave the way for a new generation of systems. But, as we move into the tail end of the third quarter, PC activity will continue to slow as demand drops. The third-quarter back to school season is also proving to be a challenging period, despite prices dropping to their lowest levels.

“We expect the year will end with shipments in the U.S. falling by 3.7%, marking the second consecutive year of contraction.”

PC makers such as No. 2 Lenovo, which operates its executive headquarters in Morrisville, will find their best opportunities in emerging markets, IDC says.

“IDC remains optimistic that PC penetration opportunities in emerging markets will form the bulwark of the market and help sustain double-digit Portable PC growth in the long run,” explained IDC senior research analyst Jay Chou.

“However, a host of all-too-familiar variables will lead to a subdued second half of the year with only consumer notebooks remaining in growth mode for all of 2012.

“Factors such as Windows 8 coupled with Ultrabooks could present a positive turn of events next year, but it also faces some initial hurdles; chief of which is that buyers must acclimate themselves to an operating system that is a dramatic departure from existing PC paradigms. The PC ecosystem faces some work to properly educate the market.”

Worldwide shipment growth is expected to grow by 0.9 percent this year, down from a forecast of 5 percent in June.

IHS iSuppli said Friday that global semiconductor chip shipments are set to fall by 0.1 percent this year. That’s down from a previous forecast for growth of up to 3 percent. It’s the first annual decline since recession-colored 2009.

ISuppli said shipments slowed noticeably compared to normal seasonal patterns in the April to June period. The weak global economy is one culprit, but most of the slowdown is in chips for PCs, iSuppli said.

On Wednesday, Hewlett-Packard Co., the world’s largest maker of PCs, said its PC sales fell by 10 percent from the same time last year. CEO Meg Whitman attributed the decline to fierce price competition, a growing preference for tablet computers and smartphones, and postponed purchases among buyers waiting for the release of Windows 8 on October 26.

ISuppli projects a 9 percent jump in chip shipments in 2013, provided the global economy manages to avoid obstacles like slowing growth in China and fiscal turmoil in the U.S.

(The AP and Bloomberg contributed to this report.)