After 'excessive weight', the most common grumble about notebooks tends to be battery life... or lack of it. This is a problem which just won't go away, and the trend towards faster processors, larger screens, more memory and generally more of everything only makes things harder on the battery that has to run the show.

Obviously the industry hasn't taken this lying down, and various clever power saving schemes have been introduced over the years, mostly centered on reducing the voltage required to run key components and inactivity timers that shut things down whenever possible.

Intel recently combined both approaches in the design of its notebook-specific Pentium III SpeedStep processors, which can detect automatically when the power source is changed from mains to battery, and react accordingly. The maximum processor clock speed drops from 600MHz or 650MHz to 500MHz (the latest 700MHz SpeedStep slows to 550MHz), and the operating voltage is reduced to 1.35V. According to Intel, this can lower power consumption by the processor to the tune of about 40 percent.

Before we go on to look at a selection of SpeedStep notebooks, there's one caveat: the processor itself only accounts for at most 40 percent of the overall power consumption by the notebook, and testing has shown that SpeedStep by itself doesn't make an enormous amount of difference to battery life. In fact the increase can be as little as 20 minutes, with 30 to 45 minutes being about average.

Perhaps now you are wondering why we've chosen to review a bunch of SpeedStep notebooks, if SpeedStep itself isn't exactly an epochal technical breakthrough. Well, the real reason to get excited about these processors is that they've elevated notebook performance to new and unprecedented heights, in some cases to the equivalent of PIII/600 business desktops. What's more, the best examples showcase a combination of SpeedStep and smart system engineering which unites this power with impressive battery life, and that's what makes this new breed of portable a significant step forward. Click the 'NEXT' link below to find out more.