All too often, product follow-ups are just minor upgrades, designed to keep up with the evolution of specs. Not so with Western Digital's My Book World Edition network hard drive. This storage box marks a complete and thorough reworking of the World Edition device--and does so with positive results.

The 1TB Western Digital My Book World Edition is a handsomely styled, well-ventilated single-drive NAS box that's notably slimmer than its predecessor (it's nearly half the thickness of the My Book World Edition II). It still comes in a glossy white finish, to distinguish it from the black desktop My Book drives. Inside the relatively slim WD chassis is a 1TB or 2TB Western Digital GreenPower 3.5-inch hard drive. On their own, those drives have posted solid numbers in our performance tests for internal drives.

Here, in the 1TB version, the performance of the new My Book World Edition is dramatically faster than its predecessor, across a wide spectrum of tasks. In the PC World Test Center's evaluation, the time required to complete our tasks was often halved--and in some cases, the differential was even more.

For example, on our virus scan test, the World Edition II required 426 seconds to complete a scan; and the new World Edition required 252 seconds. Copying files from the NAS to our host PC showed an even greater boost: The World Edition II needed 532 seconds to copy 3.07GB of folders and files from the drive to the PC, while the new World Edition NAS did so in 235 seconds. For copying large files from the PC to the NAS, the World Edition II took 674 seconds, while the new World Edition did so in 332 seconds. Copying large files to and from the NAS showed dramatic improvements from old to new, too: 455 seconds vs. 128 seconds for copying the NAS to the PC, and in the reverse 652 seconds vs. 263 seconds.

In our usage, the My Book World Edition streamed normal and high-resolution media flawlessly. It also proved easy to configure via its attractive basic- and advanced-mode, browser-based interface (the latter mode handles configuring the media-serving portion of the box). The My Book includes WD Anywhere Backup for continuous backup, and TwonkyMedia from Packet Video to serve up photos, music, and video.

While it streams all media smoothly, we did have one gripe: WD's implementation of the TwonkyMedia configuration pages seemed tacked on and didn't render properly in Firefox (some controls were partially obscured). Also, considering its mainstream consumer audience, the MyBook has numerous deep settings exposed, from MAC addresses to Shoutcast nodes for the open-source Icecast Internet radio server (though we found no way to stream Internet radio with the My Book World Edition).

--Jon L. Jacobi and Melissa J. Perenson