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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  • patentman - Monday, July 31, 2006 - link

    To avoid superparamagnetism, engineers have been increasing the coercivity, the field size required to write a bit, of the disc media. These fields are limited by the magnetic materials making up the write head that will soon effectively limit drive sizes utilizing longitudinal recording. Although additional capacities are still achievable, the drive industry will be moving to perpendicular recording technology shortly as longitudinal recording has basically hit the proverbial brick wall after being utilized for nearly 50 years."

    I wrote a pretty detailed post on the anandtech forums about this a while back. You can check it out http://forums.anandtech.com/messageview.aspx?catid...">here" (I used to post under the nickname "klaviernista"). Considering I examined and issued a lot fo the patents that are the basis of seagate's perpendicular technology, I think I am more than qualified to speak on the matter.

    Oh, and for the record, the "soft" magent under layer is never truly "written to" during the reocrind gprocess. The soft magnetic underlayer is made of a material that has magnetic domains which rotate easily in response to an external magentic field. When the write field goes across any given point in the medium, it induces the field in the corresponding point on the soft magentic underlayer to rotate perpendicular to the medium. The article is correct in saying that the result is a substantial increase in write field intensity, but neglects to mention that the fields of the soft magnetic underlayer to not remain oriented perpendicular to the media surface after the write field from the magentic head is removed, whereas the fields in the magentic recording layer do remain oriented perpendicular to the media surface.

    The whole point of usuing a soft magnetic underlayer is to allow magnetic materials with very high coercivity to be used as the recoprding layer. Why do you need a very high coercivity recording layer in high density recordng media? See the post I linked to above and read the discussed about "intergranular exchange coupling."
    Reply
  • jackylman - Thursday, July 27, 2006 - link

    In the pulldown menu, accoustics -> acoustics Reply
  • SonicIce - Thursday, July 27, 2006 - link

    Even with an extra platter to lug around, the Western Digital was quieter and cooler! Reply
  • madfly - Thursday, July 27, 2006 - link

    if you want to have the seagate hard drive cross shipped where they send you a replacement and you return the defective one back to them they charge $25, considering the hard drive cost $99, that there is a ripoff. I had this happen to me with a 250GB HD that I bought last year, so I'll be spending my money with one of the others unless the deal is ridiculous. Reply
  • Mana211 - Thursday, July 27, 2006 - link

    SPCR uses 1 meter (aka 1000mm or 200 times your stated distance) to measure SPL.

    "Each drive is measured for SPL one meter away from the top of the hard drive. Hard drive noise tends to be directional, the loudest position being directly over the top. SPL readings typically drop by 2~3 dBA/1m when measured from the side of the drive. The drive is placed on a soft foam to ensure that no vibration noise is produced during testing."

    The there is an entire category of sounds you hear at 5mm that wouldn't be noticable from outside a case.

    Take this quote from SPCR: "Consider the distance of Hardware.fr's recording microphone: 5cm from the HDD. This is a serious problem. There's no way the decibel reading can be accurate due to boundary effects. It's the same problem at storagereview.com -- not even relative differences are necessarily correct due to compression effects; the close proximity impacts every measurement similarly, reducing differences."

    http://www.silentpcreview.com/article631-page1.htm...">http://www.silentpcreview.com/article631-page1.htm... shows that the new audio recordings (not to be confused with the SPL Dba numbers) will use two recording distances:

    * One meter so that "nominal" volume, audibility, and sound character can be judged.
    * One foot (or 30 cm if you will) to capture all the details from even the quietest noise sources.
    Reply
  • tuteja1986 - Thursday, July 27, 2006 - link

    Western digital for me since i want a quiet and cool drive. Reply
  • crydee - Thursday, July 27, 2006 - link

    The WD400YR and WD500YS seem very close to performance with the Raptor, but I can't find the WD400YR on pricewatch on newegg also I read about the WD drivers having a high rate of doa? Reply
  • AdamK47 3DS - Thursday, July 27, 2006 - link

    The Seagate drive has a performance advantage with the two 160GB platters. Anandtech is still ignoring the advantages of higher platter densities. Why is that? Platter density is one of the features I look at when purchasing a new drive. It's a good indication of performance when compared to another drive of the same total capacity. You have two 320GB drives reviewed with different number of platters and yet there is no mention of this other than the table. It's very odd. Reply
  • evilharp - Thursday, July 27, 2006 - link

    Check your "price bot" settings. Currently you list the following deals for a "Western Digital Caviar® SE16"

    quote:


    AnandTech Deals

    Western Digital Caviar® SE16

    Prices
    >Buy.com $2,235.99
    >Business Computing Network $2,157.78
    >TECHONWEB $2,189.44
    >Super Warehouse $2,620.99
    >PCNation $2,478.80
    >PhotoAlley.com $2,840.05
    >cameraworld.com $2,840.05
    >iUnitek $2,479.87


    I followed the Business Computing Network link (simply due to the crazy price) and it is for a 20 unit bulk purchase.

    Reply
  • Booty - Thursday, July 27, 2006 - link

    On the last page it should be listed that the WD has a 3 year warranty for retail and 1 year for OEM - you have them switched. Reply

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