The PC notebook market continues to shift from full-sized notebooks to smaller, less expensive mini-notebooks.

The market for all portable PCs moved past 38 million units shipped in the second quarter of 2009.

Quarterly demand for Netbooks, or mini-note PCs, jumped 40 percent over the first quarter, according to DisplaySearch's latest Quarterly PC Shipment and Forecast Report. Meanwhile, this surge contrasts with notebook shipments, which grew 22 percent over the same period.

Mini-note PC screen sizes have increased steadily, from 7.0 to 8.9 and then to 10.2, the report said. Some panel makers and brands are promoting 11.6-inch mini-note displays, leading to an overlap with ultraportable notebooks.

However, the higher prices of these larger netbooks diminish their cost advantage, John F. Jacobs, director of notebook market research for DisplaySearch, said in a statement.

According to the report, former Netbook pioneer Asus has been losing sales to other manufacturers. Its rivals -Acer, HP, Dell, Lenovo, and Toshiba - have all jumped into the mini market with their own offerings.

The lower price of Netbooks has helped them win a bigger market share over notebooks in Latin America and China, notes DisplaySearch. These regions have many first-time PC buyers bypassing notebooks with lots of bells and whistles in favor of simpler but cheaper Netbooks.