Chip maker Intel introduced a two gigahertz version of its Pentium 4 mobile chip in the United States on Monday and plans to launch the chip in Hong Kong on Tuesday. The chip processes two billion cycles per second, and a 1.9 GHz chip will also be introduced. Some of Intel's manufacturing partners are already taking orders for 2GHz chips on their Web sites, and more are expected to announce the availability of notebooks carrying 2GHz systems. Intel has moved quickly on the clock-speed front since introducing its first mobile Pentium 4 earlier this year, and so has rival Advanced Micro Devices (AMD). Both companies are looking to the notebook computer market for growth as the desktop market continues to be sluggish. Desktop computers still outsell notebooks by three to one, but the notebook market grew 7.9 per cent worldwide last year, compared to a 23 per cent drop for the desktop market. Market researcher IDC recently estimated 5 per cent growth for the overall market this year. The Intel mobile Pentium 4 launch comes just weeks after Intel and AMD introduced other chips. For AMD, it was the Athlon XP 2200+, a desktop PC chip using the newer 0.13 micron manufacturing process, while Intel introduced its lower-end Celeron notebook computer chip at 1.8 GHz on a Pentium 4 core. In mobile computing, both compete against Transmeta, which began shipping its 867 megahertz chip on Fujitsu notebooks. A 1GHz version is planned for shipment with Hewlett-Packard's Evo Tablet PC this year.