Worldwide PC unit shipments worldwide grew strongly in the first quarter, driven by growth in emerging markets and among consumers in more mature markets such as the US, according to research companies Gartner and IDC.

Shipments in the quarter increased 13.1 percent from a year earlier, Gartner said. IDC reported worldwide growth of 12.9 percent, surpassing the company's forecast in March of an 11.8 percent gain.

Unit shipments of desktop and portable PCs and x86 servers totaled 57.1 million worldwide in the quarter, up from 50.5 million in the first quarter of 2005, according to preliminary numbers from Gartner. IDC counted 53.2 million shipments worldwide, up from 47.1 million in last year's first quarter.

Dell is still the top volume vendor but had unit growth of just 10.2 percent, its weakest performance since the third quarter of 2001, Gartner said. Hewlett-Packard, its closest rival, narrowed the gap as its shipments grew 22.5 percent. Dell had a market share of 16.5 percent to HP's 14.9 percent. Lenovo was third in worldwide sales, Acer fourth and Fujitsu fifth, according to the company.

Dell's shipments in the quarter were almost flat in the US, while overall shipments in the country grew 7.4 percent, Gartner reported. It was the first time Dell had posted a growth rate below the US market average, according to Gartner, commenting that the consumer market was Dell's weak point. IDC reported US growth of 5.3 percent year over year, below an earlier forecast of 6.7 percent.

The biggest growth in the quarter was in the Asia-Pacific region, where shipments were up 24.6 percent, and Latin America, which posted 22.9 percent growth, according to Gartner. Europe, the Middle East and Africa (EMEA) was the largest market, with shipments of about 19.1 million, and shipments there grew 12.6 percent. Some vendors had projected a stronger quarter in the region, according to Gartner.

In the US, consumer demand for desktop PCs was a major growth driver as total shipments hit 16.4 million. Renewed price competition boosted desktop demand.

In processors, Advanced Micro Devices continued to gain on Intel , which it has now done for seven quarters, Gartner said.