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Seagate Cheetah 36LP ST336704LW

  February 9, 2000 Author: Eugene Ra  
Evaluation unit provided by Seagate Corp.
See also: Quantum's Atlas 10k II vs. Seagate's Cheetah 36LP: A Grudge Match!

Seagate has always been a leader when it comes to increasing spindle speeds. The Cheetah 4LP, for example, was the first 10,000rpm hard disk to market- it simply had no competition. IBM and Fujitsu eventually challenged the Cheetah line, but the second-generation Cheetah 9LP was still able to hold on as the fastest drive around. It's the third generation, however, where the competition became fierce. Here we found newcomers Quantum and Western Digital matching an even exceeding the Cheetah 18LP.

As it turns out, despite a promising start in the 10k rpm market, Western Digital has bowed out of the SCSI market entirely. Thus, we're going to witness 4th-generation level products (36 gig low-profile) from four companies. Quantum is following up its blazing Atlas 10k with (get ready for this!) the Atlas 10k II. IBM's entry is the Ultrastar 36LZX. Fujitsu's next contender is the MAK3364 (we suppose they didn't like the sound of "MAI" or "MAJ"). It should be surprising to no one, however, that the first to deliver a fourth-generation product is Seagate Technology, with the Cheetah 36LP.

The latest 10k rpm beast from Seagate has specs that read like an evolutionary improvement over the predecessor 18LP model. Again, first and foremost, the Cheetah designation indicates that the drive operates at 10,000rpm, allowing for fast sequential transfer rates and reduced access times. The drive distributes its data over six platters, each holding 6.1 gigs of data. Interestingly, the 36LP's seek time remains at 5.2 milliseconds, a figure first reached by the second-generation drive. The competition is delving into sub-five millisecond seeks. Seagate, on the other hand, seems to be stabilizing the Cheetah line into a mainstay offering. Perhaps this is indication that something faster is on the horizon?

The Cheetah 18LP was equipped with a one megabyte buffer, a little bit on the small side when compared to the competition. The 36LP beefs up the figure to a more sizable four megs. Decent, yes, but a bit skimpy compared to some competitors who plan to equip their latest drives with a standard eight megs of buffer. Seagate also offers AV versions of the 36LP which feature 16 megs of buffer. In the future we hope to test an AV model to once again revisit the question of buffer size's impact on high-level performance.

As Seagate's leading enterprise-class drive, this latest Cheetah disk is backed by a five-year warranty. Seagate feels that this drive is its most reliable ever, for the first time specifying a 1,200,000 Mean Time Between Failure rating. Many realize that such figures should be taken with a grain of salt (and that such figures are almost always misinterpreted- MTBF measures failures in drive-hours of operation, not absolute-hours). Nonetheless, its testament to the maturity of the design that Seagate uses in its 10k line.

With this drive, Seagate joins Quantum as the second manufacturer to deploy Ultra160/m SCSI across its enteprise-class line.'s current testbed features an Adaptec AHA-2940U2W, a card that maxes out at an 80 meg/sec transfer rate. Though the drive features a 160 meg/sec interface, the actual platter-to-buffer transfer rate peters out at a specified 45 megs a second, well within the limits of Ultra2 SCSI. At the time of this writing, we're planning to deploy a new testbed shortly which will feature a more up-to-date Ultra160m SCSI host adapter as well as a new suite of benchmarks. The figures that follow are the result of our testing methodology as of mid-February 2000.

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The Cheetah 36LP features a measured access time that hovers around 9.1 milliseconds, about the same recorded for its predecessor. This should be no surprise since the two families' specified seek times are identical. This does place the drive's access time about 8% slower than the Quantum Atlas 10k, our reigning SCSI champion. The 36LP's increased areal density, however, allows for record-breaking sequential transfer rates. Our measurements clock the drive at 36 MB/sec. Thus, SCSI drives have finally reached the point where a single drive transferring in a predominately sequential manner has a good chance of saturating the now-venerable ultra-wide bus' 40 meg/sec limit.

The improvement that the 36LP exhibits in transfer rates over its predecessor allows it close the gap between the Cheetah and Atlas 10k lines. The Business Disk WinMark 99 run in Windows 95 places the Seagate drive about 3% behind the Atlas. The High-End Disk WinMark 99 (a test that we've noted is more sensitive to transfer rates), however, paint a different story. Here the Cheetah bests the Atlas 10k by an 8% margin, the largest difference measured when putting the two drives head-to-head. The Business WinMark run under Windows NT shows the Seagate trailing the Quantum once again by about 3%. High-End tests under NT portray a virtual dead heat, with the Atlas 10k edging out the Cheetah by a margin of less than 1%. ThreadMark under Windows 95 places the Seagate behind the Quantum by 3%, while ThreadMark/NT results clocked the drives at identical speeds.

The noise situation continues to improve with the Cheetah series. In our subjective use, we noted a very slight high-pitch whine when the drive was idle. Seeks were fairly muted for a SCSI drive. Still a couple notches over ATA drives, but definitely improved over the earlier 10k units. Outside a drive cooler, the disk operates quite warm to the touch. It's usable in our spacious testbed, but more cramped installations would benefit from active cooling.

The Safe Buy Award

Simply put, this designation means we'd purchase this product without regret. Sure, there may be a slightly better, slightly faster, and/or slightly less-expensive model from a competitor, but you can't go wrong with this particular unit. This award is applicable, of course, to all units at the top of their class, but also applies to units that, though not quite best-of-class, provide a strong showing nonetheless.Overall, the Cheetah 36LP represents a continued maturation and refinement of a line that will soon reach its fourth birthday. With the competition that's ensued, the 10k Cheetah series is no longer the easy choice for those looking for the absolute top performance. This latest Cheetah delivers performance that matches the Atlas 10k. Though its nothing to sneeze at, performance-wringing power users will likely cast a long look at the upcoming Atlas 10k two before delving in. Others, however, will note the line's maturity and the continued evolution of the 10k drive into a mainstream solution for servers and workstations alike.

Seagate Cheetah 36LP ST336704LW
Estimated Price: $950
Also Available: ST173404LW (73.4 GB); ST318404LW (18.4 GB)
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* Note: Threadmark 2.0 test results are the average of five trials.
WinBench99 test results are the average of three trials.


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