windows8Worldwide tablet shipments will grow by more than 58 percent this year, surpassing shipments of portable PCs for the first time, according to new projections released this morning by IDC. The research firm says tablets will reach 332 million units by 2015, exceeding the total PC market.

The projections are the latest sign of the dramatic change in the landscape for computing and the shift toward mobile devices. Also today, IDC said it expects shipments of traditional PCs to fall by 7.8 percent this year “as users increasingly consider alternatives such as delaying a PC purchase or using tablets and smartphones for more of their computing needs.”

The situation represents an ongoing challenge for Microsoft. Windows 8, released last fall, introduced a series of changes to help the operating system work better on tablets, but the changes have also introduced a steep learning curve for longtime Windows PC users. The company’s upcoming “Windows 8.1” update is expected to address some of the problems.

IDC previously said PC shipments in the first quarter declined by nearly 14 percent — the steepest decline on record — with wariness about Windows 8 getting part of the blame. Microsoft’s market share in tablets remains small compared with Apple’s iPad and Android tablets. Microsoft has been getting increasingly aggressive in its marketing campaigns, challenging the iPad by stacking up Windows 8 tablets vs. the Apple tablet.

“While Apple has been at the forefront of the tablet revolution, the current market expansion has been increasingly fueled by low-cost Android devices,” says IDC in its tablet forecast.

The statement continues, “In 2013, the worldwide average selling price (ASP) for tablets is expected to decline -10.8% to $381. In comparison, the ASP of a PC in 2013 is nearly double that at $635. IDC expects tablet prices to decline further, which will allow vendors to deliver a viable computing experience into the hands of many more people at price points the PC industry has strived to meet for years.”

Among other predictions, IDC says tablets with screens smaller than 8 inches — such as the iPad mini and the 7-inch version of Amazon’s Kindle Fire — will become the largest segment of the tablet market this year, representing 55 percent of overall tablet shipments.

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