The 1800+ runs at a clock speed of 1.53GHz, a slight increase over AMD's previous top-of-the-line XP 1700+ mobile processor, which runs at 1.47GHz.
Hewlett-Packard (HP) and Acer will launch notebook PCs based on the new chip today (15 July).
The HP Pavilion ze1250 is already being advertised for sale in the USA for $1,799 (£1,156), featuring a 15-inch XGA display, 512Mbytes SDRAM, 30Gbyte hard drive, DVD/CD-RW drive and an integrated Ethernet connection.
Several other manufacturers use AMD Athlon mobile processors in their notebook computers but have yet to announce products based on the latest chip. They include Sony with its Vaio range, HP's Compaq brand and Sharp.
The XP 1800+, based on a 0.13-micron manufacturing process, comes with AMD's PowerNow processor technology, which aims to balance the processing power required by an application with the need to preserve battery power.