Extermely slow transfer rate in WD Elements external HD

Discussion in 'Mac Accessories' started by lgtw, Sep 30, 2010.

  1. macrumors member

    Joined:
    Jul 14, 2010
    Location:
    Alaska
    #1
    PLEASE HELP! I am trying to use a WD Elements external HD formatted to Mac OS Extended, and the box says that the HD should have a USB 2.0 adapter, meaning it should transfer over 400 MB/s. Unfortunately for me, I've had many problems with this HD and it is now crawling at around 2.5MB/s, slower than 1.1 speeds. At the moment, it is at 750MB/93.51GB - About 21 hours. This is unexceptable, and I make HD videos, which are usually from 200 - 500 MB, and this would take AGES! I had no problems on my PC with this drive. Please help me! Should I format it to something else, get a new one, or something else? Please leave your suggestions below. Also, if you have an HD that works well, please leave it below, thanks!

    -William : )
    P.S. All ports are free, except for the one with the HD in it. All that I have hooked up to my Late-2009 21.5" iMac is my wireless Apple keyboard, and my Magic Mouse. Nothing else hooked up to the computer AT ALL!

    :apple::apple:
     
  2. macrumors 6502a

    Joined:
    Mar 19, 2008
    Location:
    North Shore, MA
    #2
    Depends on what you're copying. If it's a single, large file then yes, 2.5MB/s is a bit slow. If it is a lot of small files then that speed sounds about right.

    As for the speeds, USB 2.0 does not run in excess of 400MB/s, it maxes out at 480 megabits per second. Taking the control channel reservation into account (≈10% of the bandwidth), USB 2.0 maxes out at around 432 megabits/s or 54MB/s (8 megabits = 1 megabyte); most hard drives will not even reach that point. You're definitely hitting USB 2.0 speeds though, since USB 1 tops out at 1.5MB/s, not taking the control channel into account. How is the hard drive attached? Is it directly attached to your computer or is it connected via a hub?
     
  3. thread starter macrumors member

    Joined:
    Jul 14, 2010
    Location:
    Alaska
    #3
    It is a folder that had everything on the HD before lots of reformatting, so one folder with about 12 sub-folders, and many, many videos and such. I just can't take thet that will take an awfully long time, to a day just to move 93GB, when on my PC, I would have that done in about 30 minutes, I think it was focused more towards PC users. The hard drive is attached to my iMac through the ports on the back of the system.
     
  4. Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #4
    MB is short for MegaByte, Mb is short for Megabit, USB 2.0 has a theoretical transfer speed of 480Mb/s or 60MB/s, but in reality it is around 35MB/s with Mac OS X.

    Btw, what format/file system does that external HDD use?
    Either check via Get Info in Finder or Disk Utility.

    [​IMG]

    Btw 2, USB 1.1 offered theoretical speeds of 12Mb/s, which is 1.5MB/s, but in practical terms around 1MB/s.
     
  5. thread starter macrumors member

    Joined:
    Jul 14, 2010
    Location:
    Alaska
    #5
    Here. :\ [​IMG]
     
  6. Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #6
    That is strange.

    Can you open Disk Utility and check the Partition Map Scheme and Verify the Disk?

    [​IMG]


    Have you tried an SMC reset yet?

    Maybe also try the AJA System Test and see, if you can test the read and write speeds with that external?
    Btw, does that external HDD have a Firewire port you could use?
     
  7. thread starter macrumors member

    Joined:
    Jul 14, 2010
    Location:
    Alaska
    #7
    No, the HDD didn't come with a Firewire port, I wish it did, but sadly this isn't the case. It's had many problems of having to reformat if I eject it or accidentally unplug it, stuff like that. Sadly, I wouldn't know how to do a SMC reset even with the help of Apple. I am currently doing the AJA system test.

    [​IMG]

    [​IMG]

    [​IMG]
     
  8. thread starter macrumors member

    Joined:
    Jul 14, 2010
    Location:
    Alaska
    #8
    Here is the test /w the dashboard telling me all of the system's performance numbers and tasks (like Task Manager or Activity Monitor, but easier to check) @512MB read/write test.

    [​IMG]
     
  9. Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #9
    Here are the steps for your iMac, copied and pasted from the site I linked to.

    You can try to run the VERIFY DISK test via the Restore DVD.
    Guide on how to use Disk Utility from the restore / installation DVD.
    +​

    Nothing that i can see here, except the part about the slow speed.

    Btw, you can take screenshots of single windows, dialogs and widgets via CMD+SHIFT+4 > Spacebar > click on window, dialog, widget.
     

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