Sales of traditional desktop and mobile personal computers are expected to drop 7.6 percent this year as consumers shift to tablets and ultramobiles, a market tracker said Thursday. Worldwide devices (the combined shipments of PCs, tablets and mobile phones) are on pace to total 2.4 billion units in 2013, a 9 percent increase from 2012, according to Gartner, Inc. Device shipments are forecast to continue to grow, reaching more than 2.9 billion units in 2017, but the mix of these devices will significantly change over the forecast period.

The proliferation of lower-priced tablets and their growing capability is accelerating the shift from PCs to tablets. "While there will be some individuals who retain both a personal PC and a tablet, especially those who use either or both for work and play, most will be satisfied with the experience they get from a tablet as their main computing device," said Carolina Milanesi, research vice president at Gartner. "As consumers shift their time away from their PC to tablets and smartphones, they will no longer see their PC as a device that they need to replace on a regular basis."

Worldwide Devices Shipments by Segment (Thousands of Units)

Device Type	2012	2013	2014	2017
PC (Desk-Based and Notebook)	341,263	315,229	302,315	271,612
Ultramobile	9,822	23,592	38,687	96,350
Tablet	116,113	197,202	265,731	467,951
Mobile Phone	1,746,176	1,875,774	1,949,722	2,128,871
Total	2,213,373	2,411,796	2,556,455	2,964,783

Source: Gartner (April 2013)

Worldwide Devices Shipments by Operating System (Thousands of Units)

Operating System	2012	2013	2014	2017
Android	497,082	860,937	1,069,503	1,468,619
Windows	346,457	354,410	397,533	570,937
iOS/MacOS	212,899	293,428	359,483	504,147
RIM	34,722	31,253	27,150	24,121
Others	1,122,213	871,718	702,786	396,959
Total	2,213,373	2,411,796	2,556,455	2,964,783

Note: Devices include notebooks and desk-based PCs, tablets, ultramobiles and mobile phones.

Source: Gartner (April 2013)

As a result, the traditional PC market of notebooks and desk-based units is expected to decline 7.6 percent in 2013. This is not a temporary trend induced by a more austere economic environment; it is a reflection of a long-term change in user behavior. Beginning in 2013, ultramobiles will help offset this decline, so that sales of traditional PCs and ultramobiles combined show a 3.5 percent decline in 2013.

Worldwide tablet shipments are forecast to total 197 million units in 2013, a 69.8 percent increase from 2012 shipments of 116 million units. "Lower prices, form factor variety, cloud update and consumers' addiction to apps will be the key drivers in the tablet market," said Ranjit Atwal, research director at Gartner. "Growth in the tablet segment will not be limited to mature markets alone. Users in emerging markets who are looking for a companion to their mobile phone will increasingly choose a tablet as their first computing device and not a PC."

In the shares of operating systems (OSs) in device sales, the shift to mobile and the fight for the third ecosystem becomes more evident. Android continues to be the dominant OS in the device market, buoyed by strong growth in the smartphone market. Competition for the second spot will be between Apple's iOS/Mac OS and Microsoft Windows.

Tablets are not the only device type that is seeing aggressive price erosion. Smartphones are also becoming more affordable, driving adoption in emerging markets and the prepay segment in mature markets. Of the 1.875 billion mobile phones to be sold in 2013, 1 billion units will be smartphones, compared with 675 million units in 2012.

"The trend towards smartphones and tablets will have much wider implications than hardware displacement," said Ms. Milanesi. "Software and chipset architecture are also impacted by this shift as consumers embrace apps and personal cloud."