The market researcher also confirmed that the PC market is starting to rebound, and now expects this year's sales to be almost flat compared to the prior year's.
Boosted by a 17% year-over-year growth in notebook (including netbook) shipments, Acer had 13.4% of the 79.9 million PCs shipped globally in the third quarter, said iSuppli.
That helped it leap ahead of Dell. Hurt by sluggish corporate IT spending, Dell's sales fell 5.9% and it recorded a 12.9% share.
Another Asian manufacturer, Lenovo Corp., also had a standout quarter. On the rebound, Lenovo's shipments growing 17.2% year-over-year, giving it fourth place.
"Acer's rise to the No. 2 rank in the global PC business reflects not only its strong performance in the notebook segment, but also the historic rise of Asia as a primary force in the computer industry," said iSuppli analyst Matthew Wilkins in a statement.
Acer and Lenovo were ranked just No. 6 and No. 8, respectively, in 2003, Wilkins said.
"The Asian manufacturers are a growing force in the global PC business due to their aggressive pricing along with their ability to quickly react and embrace new developments, such as the netbook PC," Wilkins said. iSuppli is the third market tracker to note Acer's rise to number two. Both IDC Corp. and Gartner Inc. had already ranked Acer ahead of Dell.
HP remained atop the heap for the 13th straight quarter, with 19.9% of the market. Toshiba is No. 5 globally, with a 5.0% share, iSuppli said.
iSuppli also said that Q3 shipments overall grew year-over-year (1.1%) for the first time in a year, while growing 19% from the second quarter.
"The sequential and year-over-year shipment increases show that the PC industry emerged from the downturn and began to grow again in the third quarter," Wilkins said. Notebook shipments were "critical in driving growth," as they never wavered into the negative even during the worst quarters, he added.
Christmas and Windows 7 will conspire to "bring more good news for PC makers," said Wilkins. As a result, the PC market is now expected to decline just 0.9%, rather than iSuppli's earlier prediction of a 4% decline.
