Intel last week introduced a new series of Pentium 4 chips, the first volume desktop chips to feature the firm's 64bit extensions.

The new chips also introduce the SpeedStep power management technology from Intel's laptop processors to cut back on power consumption and heat generated by the chips at high clock speeds.

The Intel Pentium 4 processor 600 series, available immediately, consists of model numbers 630, 640, 650 and 660, with clock speeds from 3GHz to 3.6GHz. A 3.8GHz model 670 is set to ship in the second quarter of 2005. The new processors are expected to appear in desktop systems from enterprise vendors in the near future.

Intel said the new processors will boost performance in mainstream business desktop systems thanks to a doubling of the on-chip Level 2 cache memory size to 2MB compared with the current 500 series Pentium 4 processors.

The 600 series chips also feature Intel's EM64T 64bit extensions, which allow the system to address a larger memory space when running a 64bit operating system, such as Microsoft's forthcoming Windows XP Professional x64 Edition, due for release in the second quarter of 2005.

The new chips are also the first Pentium 4 processors to have Intel's SpeedStep technology, which throttles the chips down to a lower clock speed whenever the workload allows. This enables smaller, legacy-free desktops that organisations increasingly prefer, according to Intel technical marketing engineer David Hollway. "On laptops, SpeedStep technology is about extending battery life, but on a desktop it reduces the amount of heat produced by the processor, and so cuts the noise from system fans as well," Hollway commented.

Intel's new processors can be used in conjunction with the 915 Express and 925 Express chipsets as part of the firm's stable platform programme, which minimises changes to the drivers and software images that IT departments have to qualify.

The new chips also support the Execute Disable bit, which allows operating systems such as Windows XP Service Pack 2 to guard against buffer overflow attacks by marking areas of memory for data only.

Speculation has been rife that the 600 series will be Intel's last single-core Pentiums because dual-core chips are due this year, but Hollway dismissed this. "Dual-core chips will not cover the top-to-bottom market segments from day one," he said.