The Outsiders: Disks That Do More

• External Drives for the Office and the Road (chart)

Are you a data pack rat--obsessively archiving your e-mail or incessantly collecting digital photos and new songs? If so, your PC's internal hard drive may be getting cramped. And what about backing it all up? Whether your drive holds the hottest tunes or the dullest financial records, losing your data is a disaster. An external hard drive adds storage space and provides a safe place for your backups. We evaluated and lab-tested nine external drives: six semiportable desktop units based on 3.5-inch hard drives and three ultraportables based on 2.5-inch or smaller drives. Maxtor's OneTouch desktop drive won our Best Buy designation thanks to good performance and smooth operation (made easier by a detailed manual). The 250GB model is pricey at $350, but Maxtor sells other sizes, such as a 120GB (USB-only) unit for $200. Among ultraportables, we picked the $220, 40GB IOGear Combo 2.5-Inch Ion Drive for its compact design and relatively low price.

Choosing an external hard drive offers some advantages over simply installing a second drive inside your system. You can use an external model with multiple PCs, and as a means to shuttle data from place to place. And you don't have to crack the case to install it; you simply plug it into a USB or FireWire port in most cases, and for some models you install drivers. All but one of the drives we evaluated have a USB 2.0 interface (which we used for our performance tests). The models from IOGear, LaCie, Maxtor, Seagate, and Western Digital also have FireWire ports. Ximeta's NetDisk augments its USB connection with an ethernet port. External hard drives are especially handy for notebook PCs, which tend to have hard drives of lesser capacity than desktops and typically don't carry bays for a second hard drive.

Fast Enough?

You'll have to give up some speed with most external drives, as those with a USB 2.0 or FireWire interface can't keep up with drives that use internal parallel or Serial ATA connections. But external SATA drives should match the performance of internal products. At press time, the SATA II Working Group was still polishing up the external standard, and compliant products will probably not appear until late this year at the earliest. But CMS Products issued a prestandard kit that simply provides a pass-through for the PC's internal SATA interface to an external port you install in one of your system's slot covers. (If you own an older system without an internal SATA port, you can buy CMS's $39 SATA PCI Controller Card.) On average, the company's Velocity SATA Automatic Backup System drive completed our four file-copy tests in nearly 40 percent less time than the next-fastest drive (which used a USB 2.0 connection).

We saw notable differences in performance among the USB 2.0-connected drives. Ximeta's NetDisk was the fastest desktop drive overall, though Maxtor's OneTouch was a close second. Western Digital's Dual-Option Media Center drive was the slowest of the desktop models by about 10 percent on average. It was also slightly outpaced by two of the slower-spinning portable drives, Sony's 5400-rpm Giga Vault and IOGear's 4200-rpm Combo 2.5-Inch Ion Drive. Western Digital says that the performance hit on its product may be due to overhead from using a single USB connection to support the device's hard drive, USB hub, and card reader.