Higher tablet demand and lower Netbook sales are likely to take a greater bite out of the PC market this year than expected, according to data released today by Gartner.

Global PC shipments are now forecast to grow by 9.3 percent in 2011, reaching 385 million units, says Gartner. That marks a slight drop from the research firm's previous estimate of 10.5 percent growth for the year.

Gartner blamed the downfall mostly on shrinking demand for Netbooks but also pointed to tablets as shaking up the market.

"Mini-notebook [Netbook] shipments have noticeably contracted over the last several quarters, and this has substantially reduced overall mobile PC unit growth," Ranjit Atwal, research director at Gartner, said in a statement. "Media tablets, such as the iPad, have also impacted mobile growth, but more because they have caused consumers to delay new mobile PC purchases rather than directly replacing aging mobile PCs with media tablets. We believe direct substitution of media tablets for mobile PCs will be minimal."

The PC market itself is transitioning, notes Gartner, from "one-size-fits-all" computers to more specialized devices, all of which are designed to complement each other.

"Moving forward, PCs will no longer be a market by themselves, but part of a larger device market that ranges from smart televisions to the most-basic feature phones," Atwal said. "Within this market, consumers and professionals will increasingly use the combination of devices that best suits their particular needs."

As consumers have pulled back on their PC purchases, the industry has become increasingly reliant on the corporate world to drive sales. Gartner expects PC growth this year and next to be fueled in part by companies looking to replace their aging computers. The firm also sees the need to move away from Windows XP as a key factor that will force many businesses to upgrade to new PCs.