Tablet shipments will surpass desktop and laptop PCs in the fourth quarter of 2013, IDC predicted yesterday.

The outlook for PCs has been lowered by 10% by IDC for all of 2013, highlighting the tablet dominance in the fourth quarter, IDC said.

For all of 2013, PCs will still out-sell tablets, but IDC said tablets will surpass PC shipments for a full year by the end of 2015.

In the past few years, tablets have cannibalised PC sales. But IDC analyst Bob O'Donnell said smartphones five inches and bigger (sometimes called phablets) will start to eat into the smaller-sized tablet market - those in the 7in to 8in range - over the next 12 to 18 months.

In August, IDC lowered its 2013 tablet shipment forecast by 1% to 227.4 million partly because of the impact of phablets and wearable computing devices.

IDC also forecast that the value of all kinds of smart connected devices, which includes PCs, tablets and smartphones, will grow by 10.6% in 2013,. That growth rate will slow to just 3.1% in 2017 due to the increase in low-cost smartphones and the white-box tablet market.

Overall for 2013, the smart connected device market is expected to be valued at $622 billion, with $423 billion of that total coming from lower end smartphones and tablets.

"Lower priced devices will be a game-changer," said Megha Saini, an IDC analyst.

For 2013, IDC predicted shipments of 134.4 million desktop PCs, 180.9 million laptops, 227.3 million tablets and 1.01 billion smartphones.

Smartphone shipments will grow to 1.7 billion in 2017, while tablet shipments will grow to 406.8 million. Laptop shipments will grow to 196.6 million that year, while desktops will decline to 123.11.