By Katie Marsal

Published: 02:35 PM EST (11:35 AM PST)

Tablets and smartphones will significantly affect PC sales in the years to come, with touchscreen devices like Apple's iPad representing 10 percent of PC sales by 2014, according to a new forecast.

Gartner on Monday released its latest forecast update for PC sales. The firm expects a total of 352.4 million computers to be shipped by the end of 2010, which would be a 14.3 percent increase from last year, but is also less than Gartner's previous forecast in September of 17.9 percent growth.

Accordingly, the firm also reduced its projections for PC shipments in 2011. Gartner now believes that worldwide PC shipments will reach 409 million units next year, a 15.9 percent increase from 2010. That's less than its earlier estimate of 18.1 percent growth.

Gartner believes devices like Apple's iPad are "disruptive" to sales of traditional PCs. Released in April, the iPad is already outselling the Mac.

"These results reflect marked reductions in expected near-term unit growth based on expectations of weaker consumer demand, due in no small part to growing user interest in media tablets such as the iPad," said Ranjit Atwal, research director at Gartner. "Over the longer term, media tablets are expected to displace around 10 percent of PC units by 2014."

Gartner's analysts believe that more portable devices will eat away at sales of more traditional desktop and laptop computers in the future.

"PCs are still seen as necessities, but the PC industry's inability to significantly innovate and its overreliance on a business model predicated on driving volume through price declines are finally impacting the industry's ability to induce new replacement cycles," said George Shiffler, research director at Gartner.

"As the PC market slows, vendors that differentiate themselves through services and technology innovation rather than unit volume and price will dictate the future. Even then, leading vendors will be challenged to keep PCs from losing the device 'limelight' to more innovative products that offer better dedicated compute capabilities."

The analysis is similar to comments made earlier this year by Apple Chief Executive Steve Jobs, who said he believes that devices like the iPad are representative of a forthcoming post-PC era. He compared the growth of tablets to the migration of the U.S. automobile industry from trucks to cars.

Jobs said that trucks were originally a necessity because they were driven by farmers. But as cities grew and features like power steering and automatic transition were added to cars, they became the more popular option.

"PCs are going to be like trucks," Jobs said noting they will still be around, but they will represent a smaller number of sales.