Hard Disk Performance: HD Tach

We find HD Tach to be useful for generating random access and average read rate results in a very consistent manner. Although the burst rates and CPU utilization rate numbers are interesting they tend to be meaningless in actual application performance comparisons.

The Seagate Barracuda 7200.10 320GB has the highest average sequential read speed of 68.7 MB/s with the Western Digital drive averaging 57.1 MB/s in our comparison today. In previous testing our WD Raptor 150 lead the field with a 75.4 MB/s average, the Seagate 7200.10 750GB at 66.9 MB/s, WD RE2 500GB drive at 62.4 MB/s, WD RE2 400GB drive at 57.0 MB/s, and the WD RE16 250GB drive at 51.4 MB/s. The Seagate 320GB and WD 320GB drives finish around the 40 MB/s mark at the end of the disk. In contrast, the WD Raptor finishes with a 52 MB/s result that is more than 30% greater than the 7200 RPM drives. However, if you look at the read performance for the first 150GB on the 7200 RPM drives, both manage higher than or equal to the minimum transfer rates than the Raptor.

The random access time benchmark favors the 10,000rpm spindle speed of the Raptor which generates a result of 8.6ms. The 7200rpm drives results are close with the nod going to the WD 320GB at 13.2ms while the Seagate 320GB drive finishes at 13.3ms. The average rotational latency at 10,000 RPM is 3ms while the average rotational latency at 7200 RPM is around 4.17ms; what this means is that the head seek speed on the Raptor is significantly faster (~5.6ms) than the other drives (9.2-10.0ms). Although the Seagate 320GB drive has excellent burst rates we will soon see this does not always translate into class leading performance.

Test Setup - Software PCMark05 Performance


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  • Wesley Fink - Thursday, July 27, 2006 - link

    Actually, as strange as it sounds, Gary is correct on the WD warranty. You can check it out for yourself at http://support.wdc.com/warranty/policy.asp">http://support.wdc.com/warranty/policy.asp. OEM (bulk) drives carry a 3-year warranty and retail drives carry one year with an option to add 2 more years (to 3 total) for $14.95. Enterprise drives like Raptor carry a 5-year warranty. Reply
  • Wesley Fink - Thursday, July 27, 2006 - link

    Corrected. Reply
  • archcommus - Thursday, July 27, 2006 - link


    Speaking of performance, the drive in our IPEAK tests was at times near the bottom of the group and usually trailed the Seagate 320GB drive except in the game play, general business, and applications were heavy read requests were prevalent.

    I'm guessing it should be "...where heavy read requests were prevalent." Just a heads up.
  • Wesley Fink - Thursday, July 27, 2006 - link

    Typo fixed. Reply
  • Zaitsev - Thursday, July 27, 2006 - link

    Nice article, Gary. I enjoyed the background info on the two companies.

    A quick question: Is it possible the str of the Seagate is higher because of a higher areal density due to having only two platters vs. the WD's three? Or have I overlooked something and need to go to sleep :)

  • AkumaX - Thursday, July 27, 2006 - link

    Nice article. We win either way!!! I'd rather go with Seagate though because I've had to RMA too many WD's in the past few years.

    Does anyone know of an app that measures HDD throughput (as in MB/s, read/write or both) in realtime?
  • Calin - Thursday, July 27, 2006 - link

    I found strange how big a difference is in some bencmarks between one drive and the other (losing or winning). Anyway, each drive looks good value for money Reply
  • Googer - Thursday, July 27, 2006 - link

    PerformanceTest 6.0 (PassMark Software)
    PC Pitstop @ PC Pitstop.com (requires internet explorer)
  • Googer - Thursday, July 27, 2006 - link

    http://www.simplisoftware.com/Public/index.php?req...">http://www.simplisoftware.com/Public/index.php?req... Reply
  • AkumaX - Saturday, July 29, 2006 - link

    Sorry, HDTach is a benchmark. I'm looking for something that actually tells me how my hard drive is doing at the moment Reply

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