Intel Pentium 4

If you think we already covered the 2.2-GHz Pentium 4 (code-named Northwood), you're right (First Looks, January 29). But that was in a box way bigger than the one PC Notebook sent us. This and other notebook vendors decided to put the 2.2-GHz (and 2.0A) version of the Intel P4 into notebooks. And we can kind of see why they came up with the idea.

Unlike in the past, when using a desktop chip resulted in a mobile egg fryer, today heat is not so much a problem. Sure, designers still need to pay more attention to cooling fans and systems in a laptop than they would when working with a mobile chip. The Northwood, however, is the first desktop chip fabricated with a 0.13-micron process—the same one that debuted in Pentium III-M mobile processors. True, it is larger and requires a higher voltage (1.5 volts), which results in a higher average power envelope: 5 to 7 watts, compared with about 2 watts for its mobile counterpart. But it is not worlds away from a mobile chip in terms of thermal characteristics.

But does it perform as it would in a desktop, this hotter chip? In a word, no. Despite the better subsystems we cited earlier, a desktop chip is still a little crippled by being put into a mobile box, although not to the degree seen about five years ago. As you may recall, back then there were a slew of 200-MHz desktop chips appearing in notebooks, but they performed on a par with 133-MHz laptop chips. Strangely, the fastest mobile chips at that time (166 MHz) would always outperform the "faster" desktop processors. The sensitive environment of a laptop seemed to favor a mobile chip.

Today, our preliminary testing indicates that 2.2-GHz processors in laptops perform similarly to and maybe slightly better than the fastest mobile chips. Let's be clear, however: You still get only 1.6- or 1.8-GHz performance out of a 2.2-GHz desktop processor when it's placed in a laptop.

And battery life suffers greatly. The power-saving processor technologies are not present in desktop chips and their supporting chip sets. While the tested PC Notebook unit did keep up on the battery life test, or nearly, it did so only by housing a 6,000 mAh battery—almost twice as large as the 3,800-mAh units in the other machines.

So whether you are a fan of a particular chip vendor or just wish to find the best mobile CPU for the money, one fact remains: You no longer have to pay more for less. Thanks to the new implementations, you won't have to pay for portability and then stare in frustration at a horrible investment as it taunts you from your lap.