By Neil Hughes

Published: 10:20 AM EST (07:20 AM PST)

The buzz kickstarted by Apple with its long-awaited iPad is expected to produce a total of 10.5 million shipped tablet devices in 2010, representing a new and significant change for the PC market.

Gartner revealed Thursday its formal predictions for 2010, with the analysis firm expecting PC shipments to grow 20 percent by the end of the calendar year. A significant part of that growth will come from tablet PCs and next-generation tablet devices like the Apple iPad.

"User requirements are clearly segmenting, and the mini-notebook proved this point," said Ranjit Atwal, principal analyst at Gartner. "Vendors can no longer afford to just think in terms of traditional PC form factors or architectures. With the rise of Web-delivered applications, many users no longer need a traditional PC running a resident general-purpose operating system and fast x86 CPU to satisfy their computing needs."

He continued: "Apple's iPad is just one of many new devices coming to market that will change the entire PC ecosystem and overlap it with the mobile phone industry. This will create significantly more opportunities for PC vendors as well as significantly more threats."

On Wall Street, analyst opinions on initial iPad demand are varied, with predictions ranging from 1 million to 5 million in first-year sales. A recent report alleged that Apple will ship between 600,000 and 700,000 units at launch later this month. Suppliers said that Apple could deliver another million iPads in April.

The report follows a rumor from this week that the iPad is on track for an alleged sale date of March 26. The 3G-enabled versions of the iPad, which sell for an additional $130, will arrive a month later.

That same report suggested Apple store employees could begin receiving training on the new hardware starting March 10. It also stated that Apple intends to begin airing iPad commercials, which will emphasize the device's e-book capabilities, on TV starting March 15.

Gartner's forecast of 20 percent growth in 2010 is up from its prediction of 13.3 percent in December. The company expects home PC demand to accelerate and professional replacement system purchases to arise in the next few years.

"The PC industry will be overwhelmingly driven by mobile PCs, thanks to strong home growth in both emerging and mature markets," said George Shiffler, research director at Gartner. "Mini-notebooks are again forecast to boost mobile PC growth in 2010, but their contribution is expected to decline noticeably afterward, as they face growing competition from new ultra-low-voltage (ULV) ultraportables and next-generation tablets. Desk-based PC shipment growth will be minimal and limited to emerging markets."

And as devices such as laptops -- and now tablets -- become even more mobile and powerful, Gartner expects portable devices to drive 90 percent of PC growth over the next three years. In 2009, mobile PCs accounted for 55 percent of PC shipments, but by 2012, that number is expected to grow to nearly 70 percent.