New Windows Laptops’ Processor Stretches Battery

 A new generation of Windows laptops has arrived, powered by a new Intel processor claiming to extend battery life and by a marketing blitz promoting wireless networking. This is good news, but as is often the case in the computer industry, the hype obscures the truth.

The new processor is called the Pentium M, and it was designed from the ground up for mobile computers. One key feature of the Pentium M is that it can turn off parts of its internal circuitry when they’re not being used so that less battery power is drawn.

Another key feature is that, unlike other Intel processors, it doesn’t depend on a faster clock speed – that megahertz or gigahertz rating you see on all processors – for its efficiency and power.

Indeed, it has a slower clock speed than other Pentiums – no more than 1.6 GHz. But it is designed to wring more processing out of each clock cycle, so computer makers are claiming it is as fast and powerful as Pentiums rated at well over 2 GHz.

But you won’t hear much in Intel’s ads about the Pentium M. Instead, Intel will be pushing something called Centrino, a bundle of chips that includes the Pentium M as well as a new Intel-designed radio chip for Wi-Fi wireless networking.

You might conclude that Centrino laptops do Wi-Fi better than other laptops, or that the Pentium M or Centrino chips are needed for wireless networking. But none of this is true.

The Pentium M has no special capability for wireless networking. And the Intel-produced Wi-Fi radio chip included in the Centrino bundle is actually regarded by some computer makers as inferior to other brands of radios they were already using. Not only that, but the Intel radio used in Centrino machines doesn’t support the new, faster type of Wi-Fi networks called G or A.

However, Intel won’t allow laptop makers to label their Pentium M machines with the Centrino brand unless they use the Intel Wi-Fi radio. So, computer makers are planning to offer two different types of laptops with the identical Pentium M processor. Some will use Intel’s radio, in order to share in the glow of the Centrino marketing campaign. Others will mate the Pentium M processor with radios made by other companies and won’t be called Centrino.

With all that in mind, I have been testing four new Pentium M laptops, from IBM, Toshiba, Dell and Gateway. All are midrange models, weighing between 4.9 and 6.1 pounds, with 14-inch or 15-inch screens and CD or DVD drives. Three of the four use the 1.6 gigahertz Pentium M, while one, the Toshiba, uses a 1.4 GHz version of the processor.

I didn’t do complete tests on these machines, but focused instead on the two features Intel is stressing: battery life and wireless networking.

I did find that most of the Pentium M machines I tested offered better-than-average battery life. It’s impossible to quantify the improvement because the tested machines can’t be directly compared with older models. They have multiple revised components, not simply a new processor. For the battery test, I used my usual harsh regimen of turning off all power-saving features and playing a continuous loop of music. A more normal usage pattern, with power-saving turned on, would yield better battery life.

Toshiba Tecra M1: This $2,800 laptop was the battery champ in my tests, turning in an amazing performance of four hours and four minutes. This probably means you’d get nearly six hours in normal use with power-saving turned on. One reason is that it includes a large, nine-cell battery, but the weight is still just 5.7 pounds, including a DVD-recording drive. Wi-Fi reception in my home was good. This is the only one of the four machines I tested that will bear the Centrino brand.

IBM ThinkPad T40: This slender contender was the lightest model in my tests, at just 4.9 pounds. Its nine-cell battery produced the second-best battery life, at three hours, 37 minutes. That means it could probably top five hours in normal use. It also had by far the best Wi-Fi reception, being the only machine that could connect to both Wi-Fi networks in my house. But in typical IBM fashion, it is very expensive at $3,249.

Gateway 450: This was the heaviest and bulkiest machine in the test, at 6.13 pounds, including an eight-cell battery. But it also was the only one with a 15-inch screen (the others are all 14.1 inches), and it has the lowest price at $2,195. Battery life in my test was three hours, two minutes, which probably means around four or 4.5 hours in normal use. The Wi-Fi reception was adequate.

Dell Latitude D600: This laptop got a miserable battery life of just one hour, 46 minutes in my test, which likely means at most a three-hour battery life in normal usage. The reason may be that it uses the smallest battery of the machines I tested, with only six cells. It’s relatively light, at 5.4 pounds, and costs $2,267. Wi-Fi reception was good, and I liked the screen a lot.

The Pentium M processor is a step forward, and I advise anyone buying a Windows laptop to get one that uses this chip. But you don’t need a Centrino machine or an Intel radio to do wireless networking.

E-mail me at mossberg@wsj.com.