Looking for a laptop? Then you may have heard the hype about Intel's new Centrino Duo mobile technology. Our tests for this laptop review showed that it lives up to some claims but falls short on others.

The new chipset provides longer battery life and faster wireless data transfer than previous versions. But it doesn't deliver promised gains in application speed, memory use, 3D graphics, or video quality.

Our findings for this laptop review are based on first looks at several new laptops with the latest version of Centrino Duo. They arrived as we were completing our current Ratings  of laptops using the previous generation of chips. We're running full tests on models with the new circuitry, and results will be in our November issue.

If you're ready to buy a laptop, there's little reason to insist on the latest Centrino Duo. Laptops in the Ratings  should be fine for typical use, and prices might drop as retailers make way for the new models. The main reason to go with the new processor is to get longer battery life--say, for frequent air travel. You can tell that a laptop has the new version of the Centrino Duo if its processor is labeled T7x00, where x is an odd number. Ask a salesperson to be sure.

Here's what our first look laptop review of the new Centrino Duo models uncovered:

Battery life. We measured gains of about 35 percent with an Apple MacBook Pro and about 50 percent with a Lenovo laptop, compared with similar models using the previous chip. That translates to an hour or more of extra use.

Wi-Fi data transfers. The new wireless adapter uses a draft version of the 802.11n standard, which Intel claims is up to five times faster than 802.11g. In our laptop review tests, wireless transfers ran about 70 to 80 Mbps (megabits per second), compared with about 20 Mbps with the old Wi-Fi--impressive, but less than claimed. This can speed data transfers on your home network but won't affect Web downloads.

Application speed. Intel says the Centrino Duo is up to twice as fast as a single-processor Pentium. That might be true, but compared with the fastest dual-core processors of the most recent generation, we found in our laptop review that it was only marginally faster running common applications.

More memory for less money. Typically, upgrading your computer's memory from 1GB to 2GB should boost performance about 17 percent, at a cost of about $150. Intel says the new Turbo Memory upgrade can enhance speed almost as much, and it costs $30. But in our laptop review we found that Turbo Memory improved performance a barely noticeable 5 percent.

3D-graphics performance. We have always advised gamers seeking the best 3D performance to go for a separate video card with dedicated memory. We still do. The integrated graphics adapter in the Centrino Duo, the X3100, was faster and more reliable than older ones in the laptop review but still didn't match an ATI or Nvidia card with 128MBof video RAM.

Video performance. Intel's Clear Video technology promises sharper images using a technique called deinterlacing. This works only with some video, such as from a digital camcorder. And even then, we saw minimal improvement.

Here are other developments in laptops and desktops from a few big brands:

Apple. The MacBook Pros in our best computer Ratings  use a typical fluorescent backlight for the screen. The new 15-inch model, which we're testing for the November issue, has an LED backlight that's brighter and less power-hungry. However, images had a greenish tint, flesh tones were less natural, and colors were less saturated. The new 17-inch model, which has a conventional backlight, did a bit better than the one in the best computer Ratings .

Dell. The new Dell Inspiron 1520 and 1720 laptops differ from the models in the best computer Ratings  in a few ways. They come in more colors but are thicker and heavier. They can be configured with a Blu-ray high-definition DVD recorder (for $700), webcam, microphone, and a remote control.

On the desktop side, Dell is dropping the Dimension brand, which is now called Inspiron. The towers for the new Inspiron 530 and 531 are shorter than their predecessors but still as expandable, with a door over the USBports.

In June, Dell began selling selected desktops and notebooks at Wal-Mart and Sam's Club. Indications are that it will continue, but we have no details yet.

HP. The new dv6500t and dv9500t laptops have added the new Intel chipset and a fingerprint reader. An HD DVD player is a $400 option. Like their predecessors, in our best computer Ratings  these HP systems have Lightscribe DVD burners that can create their own labels, as well as dual-headphone jacks and expansion ports.

Desktop models have a new monitor with built-in speakers and a low-profile keyboard. You can attach accessories to the sides of the monitor or tuck the keyboard below it.