WHAT'S HOT: The new ThinkPad T40 is IBM's best one-bay notebook yet, and not just because it takes all its predecessor's best features and adds a faster processor. It boasts the T30's impressive combination of a big screen, multiple flavors of wireless readiness, and dual pointing devices in a slim notebook. Its modular bay can host a combination DVD-ROM/CD-RW drive, a Zip drive, a second hard drive or battery, or a floppy drive. What's more, you can specify an 80GB hard drive and up to 2GB of system memory.

At 5.4 pounds (without add-ons like an adapter) and a thickness of one inch, it's even skinnier than the T30.

But the real news is that the T40 is ridiculously fast, thanks to Intel's latest generation of thin-laptop processors. Faster yet cooler-running, the Pentium M lets vendors squeeze notebooks into smaller cases. Our review unit used a 1.6-GHz Pentium M chip, equipped with a generous secondary cache of 1MB, to lock down a record-breaking PC WorldBench 4 score of 124. That's about 25 percent higher than the average scored by full-size notebooks we've tested with the regular 1.6-GHz Pentium 4-M chip. In the battery life department, our review machine used a new 9-cell power pack to run almost 6.4 hours.

WHAT'S NOT: This high-end configuration of the T40, loaded with almost every bell and whistle available for the line, is pricey at $3249. One of those high-end features, the extended-life battery, adds almost an extra inch to the back of the notebook. You can order a configuration with a regular 6-cell battery, if you prefer. You won't get 6-hour battery life, but the power pack will sit flush with the back.

WHAT ELSE: IBM does the best job of any vendor in implementing dual pointing devices: Each not only has its own set of directional buttons, but both sets of buttons depress deeply to provide lots of feedback, to a level that no other notebook can match. The typing action, as on all ThinkPads, is firm yet quiet. And to suit any fingertip, three different pointing stick covers come in the box.

The T40 boasts all the same connections as the T30, including legacy parallel and PS/2 ports (but no FireWire port). It has the built-in antennas to speak three different wireless protocols: 802.11b and 802.11a Wi-Fi standards along with Bluetooth.

The main design difference between the T30 and the T40 is that the battery now comes mounted on the rear, and some connections have moved to the sides. For instance, the monitor connection has been displaced to the right side, a location that looks somewhat odd but should not inconvenience too many users. Most parts are easy to access. A lever on the bottom releases the battery, and devices pop out of the modular bay when you pull a side-release tab. The hard drive has a more convenient retaining screw than before--any type of screwdriver works with the Phillips head--but the drive's end piece is stickier (we had to force it off).

The audio in this thinner machine seems compromised--not as round, even though fairly loud. IBM still provides smoothly working buttons at the top of the keyboard for controlling the volume.

Rounding out the features is a smattering of old and new proprietary IBM goodies. For example, the lid doesn't have an Ultraport, IBM's modified USB port, but it does sport a ThinkLight, an LED that illuminates the keyboard in the dark. And a keystroke combination lets you launch a software utility for controlling all the wireless options.

The T40 bundles IBM's electronic manual, now reorganized into five new sections meant to help you locate what you need faster. Some of the section labels (such as "Learn and Configure") are a tad obtuse until you learn what they mean. Fortunately, keyword searches still take you directly to a contents and index page, and IBM has kept its useful animation sequences, such as how to remove the hard drive.

UPSHOT: Corporations that have already moved to gigabit networks or 802.11a wireless LANs, take heed: A lightweight, last-all-day notebook perfect for the office or travel has arrived. It's very thin and very fast, but also very expensive, especially in these days of $999 notebooks. On the other hand, sub-6-pound notebook computing doesn't get any better than the T40, a ThinkPad that practically incorporates the kitchen sink and makes it look svelte.

SUMMARY

IBM ThinkPad T40 $