Long considered down-and-out here at the Storage Review, Western Digital has made a huge comeback recently with the release of the blistering new 7200rpm Expert series. Combining the exceptional performance of IBM's latest drive technologies with the retail channel marketing presence of WD, the boxed Expert (418000RTL) provides hope for all those average-joe, non-storagereview-reading computer superstore customers . The "Expert" series, however, is a new line. How have the recent changes affected the venerable but ailing 5400rpm "Caviar" series? Here we'll take a look at the latest Caviar iteration, the AC420400.

A fundamental change indicates that this latest "Caviar" may be so in name only. Caviar drives, from their heyday all the way up to their decline always featured three platters in their flagship designs. This time around, however, the top-of-the-line unit features four disks. Combined with 5.1 gigs of data per platter, this allows the AC420400 to weigh in at a respectable 20.4 gigs of space. When it comes to the seek time, there's some discrepancy. The original press release (dated in December) along with the box sticker state seek time to be 8.5 milliseconds. WD's web site and promotional literature, however, list seek time at 9.0 milliseconds. We'll assume here that the more conservative of the two is true. Finally, like it's 7200rpm brother, the Caviar features an eye-popping 2 megabytes of buffer. This latest Caviar, like its last two predecessors, incorporates a collection of self-tuning feature collectively referred to as "Data Lifeguard." The drive is protected by a three year warranty.

WD has migrated its entire ATA product line to the ATA-66 interface. The AC420400 is no exception. Here at the Storage Review, we've recently incorporated the Promise Ultra66 controller into our dedicated testbed system. The AC420400 is the first drive to be tested exclusively on the Promise card. From this point forward, all ATA-66 capable drives will be tested on the Ultra66 while all ATA-33 drives will remain controlled by the testbed motherboard. For consistency's sake, we'll retest all ATA-66 capable drives already reviewed on the Ultra66 (as of this writing, the AC418000 figures have already been revised). It seems that, contrary to what one WD representative told me, most Western Digital ATA-66 drives will be shipped with ATA-66 enabled. Unsurprisingly, the AC20400's ATA-66 operation was enabled out of the box.

The newest member of the Caviar family exhibits vast improvements in speed, in many cases outracing the former 5400rpm ATA champ, the Maxtor DiamondMax 4320 by significant margins. Like the Expert, the latest Caviar forges ahead in pioneering Windows 95 performance, posting meaty 12%-18% gains in WinBench 99 over the Maxtor Drive. In WinBench 99 tests run under Windows NT, the Caviar manages to come within striking distance of the DiamondMax 4320, lagging by a mere 3% to 4%. Not a bad showing at all when one considers Maxtor's formidable showings in the NT battlefield. The drive posts decent ThreadMark scores, leading the 4320 by 19% in Windows 95 while coming up 15% short under Windows NT.

As can be expected from nearly all 5400rpm drives these days, the Caviar operates both quietly and coolly. Seeks are quite unobtrusive, barely audible over the system's power supply. The drive runs quite cool and should be absolutely no problem to integrate in even the most cramped system.

Western Digital's return to the top as a premiere hard drive manufacturer continues with the Caviar AC420400. Enviable performance and cool/quiet operation finally mean that the reign of the DiamondMax 4320 as the 5400rpm drive of choice has come to an end. True, the IBM Deskstar 25GP and Quantum Fireball CX loom on the horizon, but as it stands now, the Caviar AC420400 is the fastest 5400rpm drive yet tested here at the Storage Review.