Worldwide PC shipments totaled 90.3 million units in the fourth quarter of 2012, a 4.9% decline from the fourth quarter of 2011, according to Gartner.

"Tablets have dramatically changed the device landscape for PCs, not so much by 'cannibalizing' PC sales, but by causing PC users to shift consumption to tablets rather than replacing older PCs," said Mikako Kitagawa, principal analyst at Gartner. "Whereas as once we imagined a world in which individual users would have both a PC and a tablet as personal devices, we increasingly suspect that most individuals will shift consumption activity to a personal tablet, and perform creative and administrative tasks on a shared PC. There will be some individuals who retain both, but we believe they will be exception and not the norm. Therefore, we hypothesize that buyers will not replace secondary PCs in the household, instead allowing them to age out and shifting consumption to a tablet."

"This transformation was triggered by the availability of compelling low-cost tablets in 2012, and will continue until the installed base of PCs declines to accommodate tablets as the primary consumption device," Kitagawa continued. "On the positive side for vendors, the disenfranchised PCs are those with lighter configurations, which mean that we should see an increase in PC ASPs as users replace machines used for richer applications, rather than for consumption."

During the holiday season, consumers no longer viewed PCs as the number one gift item, Gartner indicated. Given a burgeoning variety of increasingly more attractive devices and services, consumers directed their attention elsewhere. There was uptake of very low priced notebooks as a part of mega holiday deals, but this uptake did little to boost holiday PC sales, Gartner noted.

The launch of Microsoft's Windows 8 did not have a significant impact on PC shipments in the fourth quarter of 2012. Gartner said that some PC vendors offered somewhat lackluster form factors in their Windows 8 offerings and missed the excitement of touch. New products are coming to market, and this could drive churn within the installed base, Gartner added.

In addition, Gartner revealed that HP retained the No. 1 position in the fourth quarter of 2012, thanks to good results across all products in the professional PC segment. Among the top five vendors, only Lenovo showed on-year growth and its strong performance in the quarter helped it displace Acer from the No. 2 position.

For the year, PC shipments were 352.7 million units, a 3.5% decline from 2011, according to Gartner. HP retained the top spot in the global PC market, accounting for 16% of the market. Lenovo was the No. 2 vendor with 14.8% market share. Asustek Computer showed the strongest growth among the top five vendors, with shipments increasing 17.1%.