Desktop vs. Portable external HD speed

Discussion in 'Mac Accessories' started by lankox, Jan 22, 2013.

  1. lankox macrumors regular

    Jul 5, 2007
    I've been doing some research on the differences between desktop and portable external hard drives. I was amazed at how little discussion there is concerning the speed differences. I have some preconceived ideas that I'm not sure are correct. Can someone in the know help out? Thanks!

    1) 7200rpm drives are noticeably faster than 5400rpm drives.
    2) Most desktop external hard drives are 7200rpm
    3) Most portable external hard drives are 5400rpm
    4) Desktop external hard drives will generally be noticeably faster than portable ones.

    Not sure if my logic is correct??
  2. RedCroissant Suspended

    Aug 13, 2011
    Your logic is fine. Most desktop external hard drives are the same 3.5" drives used as desktop internal hard drives.

    Most portable external hard drives are the 2.5" drives used in laptops, and due to the need to conserve power, decrease size and weight, the drive is smaller and a little bit slower.
  3. lankox thread starter macrumors regular

    Jul 5, 2007
    Thanks for the reply RedCroissant. I'm wondering if the speed difference is significant or negligible?
  4. jdechko macrumors 68040

    Jul 1, 2004
    For most consumer applications, the speed difference will be negligible. There are a variety of other factors when determining how fast a drive will be in real world use.

    For instance:

    Connections - A USB 2.0 connection will be the bottleneck in most external drives. FW800 will be faster and USB 3.0 faster still. Thunderbolt would be the fastest, though the drives are much more expensive. But if all you have is USB 2.0, you won't really see a difference in the drives.

    Data types - Disk transfers are much faster when you are copying single large files rather than many smaller files. That's because a larger portion of the file is in a continuous track; the disk doesn't have to seek out all of the files before read/write.

    Basically, for personal backup and media storage, a portable drive will take a little longer to fill up, but once the data is written, the access time will be negligible. Both drives have a high enough transfer speed to stream music and media.

    However, and I'm sure you've thought about this, portable drives are usually self-contained. Portable drives only require 1 cable to supply both power & data, while desktop drives usually need a separate power cable. If you've got a laptop, a portable drive is possibly a better purchase.

    On the other hand, portable drives tend to be more expensive per GB than desktop drives so if you want the most storage space for the money, a desktop drive might be a better choice.
  5. lankox thread starter macrumors regular

    Jul 5, 2007
    Thanks jdechko. I'm looking at buying a USB 3.0 external hard drive to hold video files to be edited for home video. I would rather buy a portable hard drive for portability reasons but also would like a fast drive. I'm just not sure if the increase in speed of a desktop drive is worth the loss in portability??
  6. RedCroissant Suspended

    Aug 13, 2011
    I had a 2011 MBP with a 5400 rpm drive and honestly couldn't tell you how much slower it was than a desktop HDD. If your goal is portability and you have usb 3.0 in mind, there should be no problem and I would go with the portable. The only downside is that the usb bus will be powering the drive instead of AC and that will decrease your battery performance a bit. If there happens to be a hybrid desktop/portable drive with a removable power cord(if it's unnecessary) then I would go for that; but I don't think it exists.

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