HP today unveiled a range of notebook computers that incorporate the AMD Turion mobile 64-bit processor.

The 64-bit notebooks are HP's first to feature the latest AMD mobile chip. The Turion debuted last month in a limited edition HP Lance Armstrong branded notebook, part of the proceeds of which will go to the cyclist's cancer foundation.

HP has started shipping models including the Turion chip in its Pavilion ze2000 series, Compaq Presario M2000 series, and Compaq Presario V2000 series.

The computers are among HP's entry level devices and have previously featured the AMD Sempron mobile processor.

Turion is the first mobile processor that offers 64-bit processing through the use of 64-bit memory extensions.

Generally dubbed x64, the technology was pioneered by AMD and has since reached desktop and server processors from both AMD and Intel, but Intel has yet to reveal a 64-bit version of its mobile Pentium M.

The order from HP is the largest deal to date for AMD's Turion and allows the chip maker to continue to compete against Intel, which has traditionally dominated the laptop market.

Notebooks are the fastest growing segment in the client computer market.

However, users will not benefit much from the 64-bit capabilities in the HP laptops because HP ships the models with a 32-bit-only version of Windows XP.

Microsoft started shipping a 64-bit version of Windows last April. But the software offers only a limited number of hardware drivers, and caters to computer enthusiasts rather than to the average consumer.

Users who purchase a new computer before 31 July can trade in their 32-bit operating system for a 64-bit version free of charge.