mid-2011 iMac external SSD boot

Discussion in 'iMac' started by efengle, Sep 25, 2017.

  1. efengle macrumors newbie

    Jul 13, 2007
    I have a mid-2011 iMac and it runs great mainly due to 32GB RAM...running Linux and Windows VMs (from external Thunderbolt HDD). The overall sore spot performance-wise is the internal (boot) HDD (3TB).

    I am thinking of getting an external SSD drive to use as the boot drive. To future proof, I want this external SSD to be Thunderbolt 3 and use a TB3 to TB2/1 cable. Since it will be a boot device, should the external SSD be independently powered or is bus powered OK?

    Would creating a Fusion drive with the external SSD and internal HDD be a bad idea? I know at least the .0 release of macOS 10.13 does not support APFS on Fusion drives.

    Feel free to chime in with any other information regarding this setup and/or recommended products.
  2. vkd macrumors 6502a


    Sep 10, 2012
    Which is the Thunderbolt 3 to TB2/1 cable that you will use?
  3. efengle thread starter macrumors newbie

    Jul 13, 2007
  4. Richdmoore, Sep 25, 2017
    Last edited: Sep 25, 2017
  5. EugW macrumors 603


    Jun 18, 2017
    Bus powered on paper should work, but it often doesn't.

    I had the same issue with a 2010 iMac. Since I didn't have Thunderbolt, I ran an external Firewire SSD. It booted up just fine and usually worked fine on bus power, but very occasionally, the computer would just hang for no reason. Firewire power is supposed to easily power a 2.5" SSD with enclosure, but once I plugged the enclosure in, all the hangs just disappeared.

    So, unless it is a very well known brand with a Thunderbolt drive design specifically built to run off bus power, then I wouldn't recommend trying to run off bus power alone. Most Thunderbolt drives are not built this way. They are built as enclosures to be fitted with third party drives, which is a problem for consistency of power utilization.

    Yes, Fusion drive with a disconnectable SSD is a bad idea.
  6. Richdmoore macrumors 68000


    Jul 24, 2007
    Troutdale, OR
    I can't offer any advice about thunderbolt 3 but I am using a Delock enclosure with a 1 tb SSD and it works great. (Although I will have to see if it is automatically changed at the new apple file system like an internal drive once High Sierra is released today.)

    I am using the corded version ($85), but there is also a bus powered version which was not available when I purchased mine. ($125).

    One more thing, these do not include the thunderbolt cable, you will need to get one in addition to these drive enclosures.

    AC Powered:

    Bus Powered:

    The big downside on the 2011 model is that this enclosure will end the thunderbolt chain. I have a Caldiget Thunderbolt station before the drive (to provide non-bootable USB 3 to the computer), and chaining works fine with it.

    If thunderbolt 3 takes off, It may actually save money to buy the older thunderbolt now and move the drive over to a new chassis/cables (which would hopefully be cheaper by then.)
  7. nambuccaheadsau macrumors 68000


    Oct 19, 2007
    Nambucca Heads Australia
    I ran that model iMac from a TB drive quite successfully with a Silicon Power TB drive. The main things that moved me on were death of Firewire and USB2 is so slow.

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6 September 25, 2017