EL SEGUNDO, CA – HP and Dell remain the world’s largest computer makers, but Acer and Lenovo are gaining, according to research firm iSuppli. Acer’s sequential mobile PC shipments rose 45.6% to 3.4 million units in the fourth quarter, said iSuppli. That beat HP, which shipped 5 million units, good for 32.8% growth. Industry-wide, mobile PC shipments rose to 23.6 million units in the quarter, up 15.7% sequentially, iSuppli said. For the year, global shipments increased 28.4% to 79.6 million units.  iSuppli predicts worldwide mobile PC shipments will rise 23.5% to 98.3 million units this year. Acer and Lenovo accounted for combined desktop and notebook shipments in 2006 of 29.8 million units, or 12.5%, up from 10.8% (23.6 million units) in 2005. Through 2011, mobile PCs are expected to post a CAGR of more than 16%, compared with less than 4% for desktops, according to analyst firm IDC. If that pans out, mobile PCs would account for more than half of all client PCs worldwide in 2011. During the quarter, Dell posted the weakest performance of the top mobile PC makers, as shipments fell 1.5% to 3.52 million units, iSuppli said. Acer's share of the global mobile PC market rose three points to 14.3%, topping fourth-place Toshiba, which reported 2.45 million units shipped. Lenovo remained in the number 5 slot, up 9.1% sequentially to 1.9 million units.