Ok, i'm confused on SATA speed ratings...

Discussion in 'OT Technology' started by Section8, Feb 10, 2006.

  1. Section8

    Section8 .

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    Ok, there's SATA 150/s and then there's 3gb/s. I'd assume that the 3gb/s is the faster of the two, but then I see that the WD Raptor 10K 150m/s drive is supposed to be the fastest drive out there at the moment.

    So what gives?
     
  2. EvilSS

    EvilSS New Member

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    Yea, it's a funny situation. See, the chipset and interface guys keep coming up with faster and faster drive standards. The problem is the drives are not limited by the interface speed today, they are limited by how fast the drive can get the data off the disk platters. So today drive RPM is usually the biggest factor in speed. The faster you can spin the disk, the faster you can get the data off the disk. There are other factors (engineering, cache, etc) but RPM is the biggest contributing factor.

    It's like a water pipe: if you can't pump water fast enough to fill one pipe, replacing it with a bigger pipe won't make a difference.
     
  3. Section8

    Section8 .

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    Oh, ok i get it. Thanks for the info :)
     
  4. deusexaethera

    deusexaethera OT Supporter

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    There are five factors that control ACTUAL drive speed:

    1. The RPM speed of the platters.
     
  5. deusexaethera

    deusexaethera OT Supporter

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    There are several factors that affect ACTUAL transfer speed:

    1. The data transfer speed of the cable and the controller.

    2. The data transfer speed of the rest of the computer.

    3. The RPM speed of the drive platters. This has two effects: higher RPMs causes data to move under the magnetic readers at a higher rate, and it also shortens the random amount of time that it takes before the requested data is underneath the magnetic readers.

    4. The speed with which the magnetic readers can move into position to read the data off the platters. If they move too slowly, they won't be in position before the data has already moved past them and the drive has to wait for the platters to spin all the way around again.

    As for SATA, there are two standards: SATA I = 150Mb/s and SATA II = 3000Mb/s. There is no single hard drive in existence right now that can provide data at the speed of 3000Mb/s, except maybe in a research lab at a hard drive company. Only a RAID (Redundant Array of Inexpensive Disks) could supply data at that speed, and even so, the individual connections to each of the hard drives in the RAID wouldn't need to meet SATA II specifications.

    Personally, I think SATA II exists for two reasons: one, so they don't have to come up with a new standard anytime soon, and two, so they can slap a big, flashy "SATA II 3.0Gb/s !!!!!!111!11one" sticker on every computer that has it.
     

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