Preliminary results from research firm Gartner indicate that PC shipments were down 4.9% to 90.3m units, a drop which it did not attribute solely to a weak economy.
"Tablets have dramatically changed the device landscape for PCs," said Mikako Kitagawa, principal analyst at Gartner, "not so much by 'cannibalizing' PC sales, but by causing PC users to shift consumption to tablets rather than replacing older PCs."
He argued that in future "buyers will not replace secondary PCs in the household, instead allowing them to age out and shifting consumption to a tablet".
The launch of Microsoft's Windows 8 in October did not make a major impact on the quarterly figures, partly because the first devices lacked a touch interface, suggested analysts.
The manufacturer Hewlett Packard (HP) regained the top position in worldwide PC shipments in the fourth quarter, moving 14.7m units, ahead of Lenovo on 12.9m, but did not grow year on year. Analysts believed this was due to the company forgoing margins in order to gain share.
In third place, Dell recorded a sharp drop in shipments in Q4, falling 20.9% to 11.6m units. Acer, in fourth place, slipped 11% to 9.7m units, while Asus, in fifth spot, saw sales grow 6.4% to 6.1m units.
For the year, PC shipments were 352.7m units, a 3.5% decline from 2011. HP was the leading brand, with 16% of the market, followed by Lenovo on 14.8%.
Among the top five vendors, Asus showed the strongest growth, with shipments increasing 17.1%. Lenovo, on 14.2% was the only other top five brand to increase shipments.
Data sourced from Gartner; additional content by Warc staff