Western Digital VelociRaptor WD3000BLFS
Access Time and Transfer RateFor diagnostic purposes only, StorageReview measures the following low-level parameters: Average Read Access Time- An average of 25,000 random read accesses of a single sector each conducted through IPEAK SPT's AnalyzeDisk suite. The high sample size permits a much more accurate reading than most typical benchmarks deliver and provides an excellent figure with which one may contrast the claimed access time (claimed seek time + the drive spindle speed's average rotational latency) provided by manufacturers. Average Write Access Time- An average of 25,000 random write accesses of a single sector each conducted through IPEAK SPT's AnalyzeDisk suite. The high sample size permits a much more accurate reading than most typical benchmarks deliver. Due to differences in read and write head technology, seeks involving writes generally take more time than read accesses. |
WB99 Disk/Read Transfer Rate - Begin- The sequential transfer rate attained by the outermost zones in the hard disk. The figure typically represents the highest sustained transfer rate a drive delivers.
WB99 Disk/Read Transfer Rate - End- The sequential transfer rate attained by the innermost zones in the hard disk. The figure typically represents the lowest sustained transfer rate a drive delivers.
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The VelociRaptor turns in a measured average read access time of 6.9 milliseconds (ms). After accounting for the 3 ms associated with a 10,000 RPM spindle speed, WD's latest is left with an average read seek time of 3.9 ms and thus bests the manufacturer's 4.2 ms claim. Average write access times weigh in at 7.6 ms. Overall, the VelociRaptor turns in competitive access times when contrasted with the Cheetah NS.
Outer zone transfers for the drive hit 119 MB/sec, a 35% improvement over the numbers achieved by the WD1500ADFD. Our particular sample exhibits some jaggedness in the outer tracks though the dips are not erratic enough to raise performance concerns. Rates decay down to a still-peppy 81.7 MB/sec.
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Some Perspective It is important to remember that access time and transfer rate measurements are mostly diagnostic in nature and not really measurements of "performance" per se. Assessing these two specs is quite similar to running a processor "benchmark" that confirms "yes, this processor really runs at 2.4 GHz and really does feature a 400 MHz FSB." Many additional factors combine to yield aggregate high-level hard disk performance above and beyond these two easily measured yet largely irrelevant metrics. In the end, drives, like all other PC components, should be evaluated via application-level performance. Over the next few pages, this is exactly what we will do. Read on! |