Laptops have grown up. Once wimpy, they now come loaded with features that make them fully functional alternatives to desktop PCs. But even a modest six-pounder can feel like 60 pounds after lugging it around for a day. The solution: Grown-up laptops need to get smaller -- but not so small that you can't actually do work on them.

If you need a truly portable portable, there are a lot of really sweet ultralight laptops, three pounds or under, out there. There's also bad news: first, that they're expensive (half the size means twice the price); second, that with ultralight laptops, everything becomes a compromise.

Some of the trade-offs are obvious; for example, the screens are going to be smaller. (Like you hadn't thought of that, right?) Others are more subtle. Because weight is the critical design factor, some things you might take for granted on a bigger machine may be missing, like a CD-ROM/DVD drive. Batteries are smaller, which means processors are going to be less powerful, which means that for some demanding applications, like recording high-definition video, an ultralight laptop may not be a satisfactory choice.

And when a PC is that small, ergonomics becomes an issue. Not only is the keyboard likely to be constricted, but the mouse-equivalent device, a touchpad or a TrackPoint, gets less real estate as well, and become harder to use. If you do a lot of graphics work – photo editing, for example -- precise cursor control means you'll probably wind up carrying a USB mouse with you, which ups the size of your kit. Some ultralights are so thin there's no room for a VGA connector, so if you use your laptop for presentations and are constantly plugging it into a video projector, that could be a problem. As a result, the central question I brought to this review was: Can an ultralight laptop be small enough to take with me, and yet big enough to be functional?

I collected three ultralight laptops to work with for this roundup: the Fujitsu Lifebook Q2010, the Lenovo ThinkPad X60, and the Sony VAIO VGN-TXN15P. The three machines have a lot in common: They all came with Windows XP Professional installed. All three run Intel's Graphics Media Accelerator (GMA) 950 mobile graphics chipset, which provides 128 Mbutes of dedicated RAM and borrows another 96 Mbytes from the operating system. All three are equipped with Wi-Fi and Bluetooth, and offer some sort of optional wireless wide area networking from a third-party service provider. All three also came equipped with fingerprint scanners for security (though it's not standard equipment on the ThinkPad).

But beyond that, each manufacturer has dealt with the trade-offs of getting big functionality out of a small package very differently. The Fujitsu Lifebook Q2010 is the thinnest and lightest, at a mere 2.2 pounds, yet has the biggest screen. The Sony VAIO VGN-TXN15P is the smallest, but it's big enough to include an optical disk drive (which is very important to me, because I install a lot of software, burn a lot of discs, and play a fair amount of music and DVDs). The Lenovo ThinkPad X60 has the most powerful processor and the best ergonomics, but the least satisfactory screen.

Fujitsu Lifebook Q2010 The Lifebook is the lightest of the three ultralights -- so light, at a mere 2.2 pounds, that it almost feels like it's an empty case, a "for display only" PC. But once the case is opened and the machine turned on, it's obviously a working PC, and a good one at that.

The Lifebook is all about delivering the biggest, brightest screen in the lightest possible package. The display is 10-5/8 x 6-3/8 inches, with a 12.1 inch diagonal. It runs at resolutions of up to 1,280 by 800 pixels, which give its screen a width-to-height ratio just a smidgen less than the 16:9 aspect ratio of the panoramic format. It uses LED backlighting, which makes the display wonderfully, dazzlingly bright -- bright enough to work with in daylight. The crispness of the screen offsets the small size of displayed text, but for me, this is just about the minimum size that I'd want to work with for long stretches.

Unfortunately, the Lifebook has no optical drive for playing CDs and DVDs and burning disks. Not very surprising, since it's very close to the size of a sheet of paper: 8-5/8 x 11-5/8 x 3/4 inches with its standard battery. The Lifebook is so thin, in fact, that there's not enough real estate around the edge for the standard connectors. (It does include a PCMCIA slot, two USB connectors, an IEEE 1394 (FireWire) port, and an SD card slot.) As a result, if you need a VGA out connector (and you will if you use your laptop to make presentations) or an Ethernet connector (and you will if you use your laptop to connect to the Internet from hotel rooms) you have to carry the included adapter cable that provides these two connectors.

The Lifebook and the Sony both run Intel's ultra-low voltage single-core 1.2-GHz U1400 processor. It's very easy on the battery, which is good because the smaller of the Lifebook's two batteries makes the machine fashionably thin, but limits operating life to a couple of hours, more or less. The larger battery adds a half-inch bump along the back of the machine, but powers it for perhaps two to three times that. (Both batteries come standard with the PC, a nice touch.)

The keyboard squeezes 82 keys in a space of just 10 x 3-1/2 inches; in order to do that, some of the keys are less than standard size. Still, the keytops are slightly dished and have good touch, if not much travel. After a few minutes of working with the Lifebook, my hands adapted to the spacing.

The touchpad is more problematic. It's a tiny 2 x 1-1/2 inches, and it takes two finger strokes to move the cursor completely across the screen. Its buttons are slightly recessed, and I needed to give them an extra push to make them work. (One little design plus is the positioning of the fingerprint scanner between the buttons, where it also functions as a scroll wheel.) A mouse is strongly advised.

Since the Lifebook lacks a built-in optical drive, you have to compensate for this with either an optional ($499) docking station with built-in optical drive, or an external drive that runs off its own internal battery and needs a separate charger ($199 for a CD/DVD-RW, $269 for a dual-layer DVD). Neither is a very satisfactory solution, because both add bulk and weight to your travel bag -- with the larger battery, power supply, VGA/RJ45 adapter, and the external optical drive (along with its cable and power supply), the Lifebook weighs in at about five pounds. It's not that much of an advantage over a standard-sized laptop.

On the other hand, if there's somebody you want to impress, just slip a Lifebook out of your bag to check your calendar. It has the highest cool factor of all three machines -- so sleek it would be a finalist in any Windows laptop beauty contest.

Lenovo X60 The Lenovo X60 runs an Intel Core 2 Duo chip, which makes it a little powerhouse at just about 2-3/4 pounds (with its six-cell battery installed). Interestingly, while the review machine came equipped with the 2-GHz T7200 with 4 Mbytes of Level 2 cache, you can't buy the X60 equipped that way on Lenovo's Web site, where the option is for the 1.83-GHz T5600 with 2 Mbytes of Level 2 cache, so set your performance expectations accordingly.

Either way, the Core 2 Duo is a considerably faster processor than the 1.2-GHz U1400, which is used in both the Fujitsu and Sony ultralights. But it uses considerably more power, too -- it's rated at a thermal design power of 34 watts, compared to the U1400's 5.5 watts. (That means the ThinkPad is turning battery power into heat at seven times the rate of the Lifebook and the Sony.) That's one reason you'll probably want to buy the larger nine-cell battery with the X60 (even though it boosts its basic weight from 2-1/4 pounds to about 3-1/2 pounds).

This is clearly a ThinkPad. It has the same businesslike matte black look and incredibly solid feel that made the ThinkPad a classic, even though its dimensions of 10-3/4 x 8-1/4 x 1-1/2 inches make it a miniature by the standards of recent models. Still, its Core 2 Duo gives it a decided advantage, and other options are available (like 2 Mbytes of RAM and a 120-Gbyte hard drive) that mean even this small package can be set up as, say, a demo machine, running both a server and client software.

Even without the optional docking station, the ThinkPad carries the full complement of connectors and ports: PCMCIA, Ethernet, modem, IEEE 1394 (FireWire), VGA, SD card slot, and three USB connectors. The number of USB connectors, in particular, is critical on these small machines. If you only have one or two USB ports, and you have to add an external optical drive and a mouse, and want to plug in anything else, like a charger for your cellphone or a flash drive, you'll soon find yourself carrying a USB hub around.

The 1,024 x 768 12-inch-diagonal screen is a classic, too -- classic 3x2 display proportions, and, unfortunately, a classic TFT fluorescent backlit screen that just isn't in the same class as the LED-backlit screens on the Fujitsu and Sony models in terms of brightness and sharpness.

The keyboard, however, puts the X60 back in the race. The X60's keyboard carries on the great ThinkPad tradition with the best touch and most generous key spacing of the three laptops. Even though the ThinkPad is 3/4 inch narrower than the Lifebook, its keyboard is wider. The keytops are dished to help you position your fingers, and the key travel is longer as well, so the experience is more like a desktop keyboard.

Even better is the X60's pointing device. You may love the IBM TrackPoint or hate it, but for me that nubby little joystick device easily beats out the tiny touchpads on the other two PCs for sensitivity and usability.

Like the Lifebook, the X60 doesn't have room for an optical drive, but you can buy an optional docking station or external drive. The docking station is easier to use than the Lifebook's -- no cables or additional power supplies -- but it adds two pounds to the weight of the laptop. The external drive is half that, but adds a tangle of cables and a wall-wart power supply.

While it's fun to accessorize, these gizmos run up the cost: the X60 with Bluetooth begins at $1,500 on Lenovo's Web site, but extra memory and a 120GB hard drive, the docking station, and the little extras like $30 for the fingerprint reader and $250 for a WWAN adapter quickly run the tariff up to the $2,200 neighborhood. Businesslike indeed.

Sony VAIO VGN TXN15P
With three ultralight laptops sitting there winking their power lights at me, which one would I reach for first? The Lifebook is the lightest. The ThinkPad has the best keyboard. But it's the Sony VAIO VGN TXN15P that my hand falls on most often. At 2.75 pounds and a minuscule 10-7/8 x 7-3/4 x 1-1/4 inches, it's more like carrying a paperback book than a PC. And it's the only one of the three with a built-in optical drive.

When I was lining up PCs for this review, I thought that an optical drive would be a requirement, because one of the major uses for an ultralight laptop is entertainment: playing music and DVDs and games. After working with all three machines, I'm no longer sure a built-in optical drive is absolutely necessary.

While it's awkward to install software when you have to hunt up an external drive and connect all the cables, a docking station with an optical drive and some thinking ahead removes about 90 percent of that awkwardness. You can do what you need to do with disks before you take the laptop on the road. After than, you can download software and transfer files over the Web, using flash drives, or over LANs. So when I wasn't installing software, the Lifebook and ThinkPad were very usable PCs.

But a built-in drive can save you all that work. Sooner or later you will absolutely need it, and if it's there, you'll have it. When it comes in a package as small as the Sony why not have it?

The optical drive isn't all the Sony's got to offer, either. Its audio is a plus. The sound from the Sony is the best of the three ultralights, and the audio capabilities are just as important for video as they are for music. That doesn't mean the Sony's sound is great compared to a larger laptop or a desktop system, but it is the least unsatisfactory. With the other two PCs you'll probably be using headphones or adding external speakers if you want to listen to music or play DVDs.

The Sony's small size is both an advantage and a disadvantage. It's almost small enough to fit into a coat pocket, but that constricts the size of the screen severely. The 11-inch diagonal screen is the smallest of the three reviewed here, and at 1366 x 768 pixels the most emphatically panoramic. It's 5-1/2 inches high, and displays text at about half the size of a 19-inch desktop monitor. The display is extremely bright and diamond-sharp, which makes it usable, but I found that zooming in on documents to 150 percent of normal size was much more comfortable for viewing. Video display is excellent -- standard 3 x 2 movies play at an effective nine-inch diagonal, bigger than many dedicated portable DVD players -- but other applications that couldn't be zoomed were sometimes problematic.

Despite its size, the Sony finds room for the necessary connectors and ports: RJ45 Ethernet and RJ11 modem connectors, a PCMCIA slot, a Memory Stick PRO slot, an SD card slot, an IEEE 1934 connector, and two USB 2.0 connectors. And the Sony's battery life is a plus: almost four hours with the standard battery. (An extra-capacity battery is also available for a pricey $299.)

The Sony's biggest drawback is its keyboard, which is designed for fashionistas rather than touch typists. It's not all bad -- the dimensions are about the same as the Lifebook, but the keys are better laid out so that no keys are squeezed down. But the keycaps are smooth metal and perfectly flat, with no raised edges to help finger positioning.

In fact, the Sony gives the impression of having been designed as much for style as for ergonomics. It's an art object, computer-as-jewelry -- and when you buy high-quality jewelry you don't expect it to be cheap do you? The current model of the VGN, the VGN-TXN17P, is a slight upgrade from the VGN-TXN15P I received for review, but comes with the same features, including an Intel U1400 processor, and will cost you $2,450 -- about a thousand dollars a pound. While Sony does make a port replicator that lists for $200, having the optical drive built in makes this extra expense less necessary than it is with the ThinkPad or the Lifebook.

ConclusionsWhile no one of the three ultralights offers the ideal combination of features, each one has its strengths:

So, can an ultralight laptop be small enough to take with me, and yet big enough to be functional? Absolutely. With bright, sharp screens, usable keyboards, acceptably fast processors, hard drives big enough to carry a variety of installed applications and a lot of data, and networking and connectivity equal to or better than much bigger computers these little machines are big enough for real jobs.