In past StorageReview.com tests the Quantum Atlas II and Atlas III fared poorly on our single-user machine-oriented tests. The Viking series, on the other hand, turned in excellent scores, proving to be a great drive for the SCSI user on a budget. We're in a period of consolidation, though; with most manufacturers having debuted 10k rpm models. 7200rpm lines are being combined into a single offering. Thus, instead of both a Viking III and an Atlas IV, we have only the Atlas IV representing Quantum's entry as both a budget SCSI drive and an enterprise-class server unit.

The Atlas IV packs 18.2 gigs of data on just four platters, yielding an areal density of 4.6 GB/platter- a level previously found only on ATA drives. The disk features a very competitive 6.9 millisecond access time. A fairly standard 2 megabytes of buffer accompanies the drive. Quantum backs the Atlas with a 5-year warranty.

Like it's 10k rpm brother, the Atlas 10k, the Atlas IV is an Ultra160/m SCSI unit. Though supposedly backwards-compatible with "legacy" SCSI host adapters, our testbed, featuring an Adaptec 2940U2W SCSI host adapter, required "hard termination" via a jumper shunt on the board itself. No LVD Ultra2 SCSI drive, including the Atlas III, ever required such termination to operate reliably.

The Quantum Atlas IV turned in the best scores to date from a 7200rpm SCSI drive, in most cases besting the previous champ, the Western Digital Enterprise WDE18300. Business Disk WinMark results run under Windows 95 place the Quantum 8% faster than the Western Digital drive. High-End WinMark tests yield similar results, with the Atlas outgunning the WD drive by 9%.

Windows NT results are much closer. Here the Quantum falls behind by 2% in the Business WinMark while edging ahead in the High-End WinMark by 4%. ThreadMark results in both operating systems favor the Quantum: the Atlas places 12% higher than the Enterprise in Windows 95 and 8% higher in NT.

Noise and heat levels of the Atlas were, overall, quite close to the Enterprise's enviable levels. Seeks were perhaps just a tad louder, with nonexistent high-pitch idle noise. Exemplifying an ever-lessening concern for 7200rpm drives, heat was quite manageable. The drive runs warm, yes, but should be fine in any well-ventilated case without a drive cooler.

The Enterprise WDE18300, considering its status as "first to the market," enjoyed quite an extended reign. The IBM Ultrastar 18ES and Seagate Barracuda 18LP, representing competing offerings from SCSI heavyweights, failed to displace WD's fighter. It was left to the latest iteration of the Quantum Atlas--a line that has previously performed poorly-- to take the crown. With its ATA-like areal density, the Quantum manages to muscle its way to the top. It even features Ultra160/m SCSI, a forward-looking interface, although it is hard to imagine Ultra2 SCSI's 80 MB/sec limit being a factor even in most multi-drive systems. Even so, the Atlas IV combines best-of-class performance with more than acceptable heat and noise levels to take its place as StorageReview.com's 7200rpm SCSI recommendation.