The looming threat of running an unsupported OS wasn't enough to save PC shipments from continuing their slide in the first quarter.

Worldwide PC shipments fell by 4.4% in the first three months of the year to 73.4 million units, IDC said yesterday.

The expiration of Windows XP, support for which ended this week, did prompt some businesses to refresh their PCs. And slower demand for tablets, as the market becomes saturated, may have helped lift laptop sales slightly.

But sales were down overall, and the trend toward more mobile devices is unlikely to stop, IDC said.

In a separate report yesterday, Gartner also said the XP upgrade cycle eased the decline of PC shipments slightly. But it too said PC shipments were down overall, by 1.7% from the same quarter a year earlier.

With an estimated one-third of PCs still running XP, computer upgrades will continue and soften the rate of decline in the PC market, said Loren Loverde, programme vice president at IDC. But most of those upgrades are done.

"If you look at the number of systems coming off XP, the fastest transition would have happened in 2012 and 2013," he said.

For the year, IDC projects that PC shipments will decline by 6.1%, an improvement from a 9.8% decline last year, thanks to improving economies around the world.

But worldwide PC shipments have now declined for eight consecutive quarters, and there's no silver lining in sight.

"The passing boost from XP replacements, constrained consumer demand, and no clear driver of a market rebound are expected to keep growth below zero going forward," Rajani Singh, a senior research analyst at IDC.

PC users aren't huge fans of Windows 8.1, but the number of touch systems being sold is growing and other OS options are limited, Loverde said. It may be hard to get users to ever really love Windows 8, he said, but the 8.1 updates make the experience more palatable.

"In many ways it's just a train you can't stop. If you want a PC you're probably going to get it with Windows 8.1," Loverde said.

The top three PC makers, Lenovo, HP and Dell, all recorded growth in shipments, but sales plunged for Asus and Acer, which rounded out the top five.

Lenovo shipped 12.96 million units in the first quarter, up 10.5% year over year, giving it nearly 17.7% of the market. HP was on its heels, with shipments up 4.7% to 12.6 million units, for 17.1% of the market.

Dell's shipments increased 9.3%, while Acer's were down 20.2% and Asus' down 8.1%. The "other" category of smaller vendors, who account for 40% of the market, saw their shipments decline 13%.