Are external HDD's with power supply inferior

Discussion in 'Mac Accessories' started by MacSeeker, Nov 10, 2014.

  1. MacSeeker macrumors newbie

    Nov 10, 2014
    Hi everyone!

    I have 2 X 500Gb external WD HDD that have separate power supplies.
    I know newer HDD can get power from the USB ports directly and I use them on my newer Macs.
    However, I have a 2008 iMac 24 inch, and was wondering if it is safe to use the above mentioned HD.
    Does the fact that these have external power supplies make them prone to more damage?

  2. bennibeef macrumors 6502

    May 22, 2013
    If you mean by "newer" HD's 2.5 inch harddrives instead of 3.5 inch harddrives which need a external power supply then theres your answer. The bigger ones need external power because the usb bus cant supply that much. For the smaller ones thats enough.

    External or no external power supply - there is no "safer" either way
  3. MacSeeker thread starter macrumors newbie

    Nov 10, 2014
    indeed the ones with the power supply are 3.5 inch ones.
    so that means If the power fails (i.e. electricity goes down because of a storm), they aren't a higher risk than the ones that take power from a USB, in this example, a macbook that can continue to supply electricity?
  4. bennibeef macrumors 6502

    May 22, 2013
    Well looking from this side, if your power goes out with a drive with external power supply the drive will go out as well. The macbook wont be able to keep it mounted. And if you where writing to it at the moment there might be data loss.

    That wont be a problem with the smaller 2.5 ones.

    If you live where there are many power-outs thats maybe something to think about. The downside of the smaller ones is, they are smaller in size and what they can store on it. That means you wont find 4-6TB drives anytime soon.
    If the power is a real problem you might want to think about a UPS.
  5. MacSeeker thread starter macrumors newbie

    Nov 10, 2014
    Thanks again!

    Yes, in winter, unfortunately the power isn't very reliable.
    I thought that some drives had an 'auto-park' thingy if the power fails, but I guess its better not to take a chance, especially for the iMac.
    I guess, I could use those on the macbooks (I have 2 macbooks as well)

    a decent UPS costs more than a new external 1TB USB HDD without a power supply.
  6. bennibeef macrumors 6502

    May 22, 2013
    There is autopark especially for shocks in laptops but if the last data buffer cannot be written the data may be lost.

    If you are using the drives with an iMac it doesnt really matter, if the power goes out the iMac would be out too.
  7. R2D2WD macrumors newbie


    Sep 23, 2014
    Hi, MacSeeker

    Bennibeef is right, the HDDs that require power supply are the 3.5'' ones, because they require more power. There should be no difference in quality of the drives, only in capacity. Some users take a 3.5'' drive and use a Y-cable, which powers the drive through two USBs and a SATA connection.
    Power shortage really may cause some issues if it happens in a moment of disk usage but it is unlikely to be a serious physical damage. Of course, all depends on the reasons for the power failure.
    If you have constant power failures, maybe the best solution really is to use a 2.5'' drive with those Macbooks.

    Hope this helps
  8. MacSeeker thread starter macrumors newbie

    Nov 10, 2014
  9. Fishrrman macrumors G5


    Feb 20, 2009
    [[ Are external HDD's with power supply inferior?]]

    No. They are "equal to" and in some cases, BETTER than drives with no power supply option.

    If a drive needs more power than the Mac USB port can provide, it's not going to spin up, or, it may "spin up half way", but still fail to mount on the desktop.

    In that case, you can use the power supply to get the drive running.

    If the Mac in question is already supplying USB port power to -other devices-, the drive in question may not mount -- even though it might have mounted with no other devices connected.
  10. rigormortis, Nov 14, 2014
    Last edited: Nov 15, 2014

    rigormortis macrumors 68000


    Jun 11, 2009
    I've found that 2.5" seagate hybrid drives require extra power. or the drive starts making beeping noises.. it will even disconnect all by itself. and once it starts beeping, the drive is hot to touch. indicating its not spinning.

    specifically the st500lm0

    i think you should all check your drives before you assume that usb power is okay. i don't like the current trend of usb powered sata enclosures. usb cannot put out 5 watts. i looked at a hitachi. its okay cuz it asks for 5 v 700 ma, which is 200 ma above standard usb but still okay i guess. , but some 2.5 " drives require more power

    even the newest macs can't put out more then 2150 Ma
  11. Ray2 macrumors 6502a

    Jul 8, 2014
    Power supplies go down. When used hard, the heat kills them. Externals are a lot cheaper and easier to replace. I try to limit bus powered drives to limited use only.

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