Do USB 3 & Thunderbolt external Hard Drives need separate power?

Discussion in 'iMac' started by spinstorm, Jan 1, 2013.

  1. spinstorm macrumors 65816

    Joined:
    Sep 14, 2007
    #1
    As I said in the title - I hate having to use a separate power cable for an external HDD.

    Does USB3 and Thunderbolt need separate power?

    I'm after a cheap 2TB backup HD that doesn't need separate power.
     
  2. WilliamG macrumors 604

    Joined:
    Mar 29, 2008
    Location:
    Seattle
    #2
    If you buy something like the Western Digital MyBook 2TB 2.5" USB 3.0 drive, then no you don't need power. Very few, if any, laptop drives need power connected via Thunderbolt or USB 3.0.

    I've been using that above 2TB drive with no problems, and also two Thunderbolt SSDs. No power cables.
     
  3. Arman macrumors regular

    Joined:
    Aug 27, 2008
    Location:
    SoCal
    #3
    No not if they are running SSD or laptop drives within. However, larger capacity drives which use 3.5" desktop drives will need external power.

    Example here
     
  4. Apple Corps macrumors 68030

    Joined:
    Apr 26, 2003
    Location:
    California
    #5
    Some do, some don't.

    There have been reports that some ssds running off bus power perform at less speed than if operating from a powered enclosure.
     
  5. COrocket macrumors 6502

    Joined:
    Dec 9, 2012
    #6
    http://www.amazon.com/Passport-Portable-External-Drive-Storage/dp/B005HMKKH4

    Above is a portable (2.5") drive. To my knowledge 2TB is the largest portable drive available. They are found in laptops and don't require external power. on the other hand, desktop (3.5") drives needs power. That's generally the quick way to figure whether you need external power when you are shopping.
     
  6. garycurtis macrumors 6502

    Joined:
    Sep 15, 2010
    Location:
    Los Angeles & Northern California
    #7
    A 500Gb Toshiba Canvio running USB 3 requires no power adaptor.
     

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