Fusion replacement options

Discussion in 'iMac' started by bunger, Oct 23, 2016.

  1. bunger macrumors 6502

    Mar 1, 2007
    I have a 2012 27" iMac with 1TB Fusion drive and Time Machine backups.

    Last night the drive failed and I am not entirely certain whether it is the HHD drive or the on-board 128GB SSD drive.

    Either way, I want to ditch the Fusion config and just replace with a 1TB SSD drive.... but I have a couple of questions:

    How do I disable the Fusion configuration?

    What is the easiest route to do that - pull both drives and just replace the SSD drive, or just the HDD drive, or? Replacing the HDD is cheaper and slightly less difficult, but...

    Will recovering from my Time Machine backup somehow try to re-enable the Fusion config?

    Thanks in advance!
  2. chscag macrumors 68040


    Feb 17, 2008
    Fort Worth, Texas
    Just pull both drives and replace it with the SSD. I'm not sure about this but you may need to use a special cable provided by OWC (Mac Sales) so that your fan does not rev up like a 747 on take off. I know that it's required if you replace the HHD combo fusion drive with a non Apple drive combo, but not sure if it's needed when replaced by a pure SSD. You can give OWC a call on their toll free line or chat line and ask. Their tech support is great.
  3. tubeexperience macrumors 68040

    Feb 17, 2016
  4. bunger thread starter macrumors 6502

    Mar 1, 2007
    This is amazing information - thank you for putting all of that together!

    Because I am not sure which drive actually failed - IF the SSD drive failed, would it still matter if it left it in place?
  5. tubeexperience macrumors 68040

    Feb 17, 2016
    It doesn't matter.

    Just make sure that you set "Startup Disk" to boot from your new SSD, so it won't boot from the other drive.
  6. bunger thread starter macrumors 6502

    Mar 1, 2007
    Gotcha. So I am assuming I break the Fusion drive configuration first, replace the HDD with a SSD, then proceed as usual?
  7. tubeexperience macrumors 68040

    Feb 17, 2016
  8. ZipZap macrumors 603

    Dec 14, 2007
    Perhaps the fusion drive separated. can be fixed without opening in store.
  9. bunger thread starter macrumors 6502

    Mar 1, 2007
    I disabled Fusion and only the SSD is available, so I'm nearly certain the HDD has failed.
  10. Samuelsan2001 macrumors 604

    Oct 24, 2013
    That Is most likely ssd's are pretty solid, HDD's usually last between 4and 6 years. Replace with a 1tb SATA SSD reinstate the fusion drive and have a super fast fusion.
  11. bunger thread starter macrumors 6502

    Mar 1, 2007
    I am going to replace with a 1TB SSD, but I probably won't re-enable Fusion. I don't see enough benefit for that at this point...
  12. EnderBeta macrumors 6502a


    Aug 5, 2016
    It is sort of like Raid0. You can have more speed and a higher probability that the array will fail if you combine the two drives. However if you combine them you have one larger pool of storage that manages itself.

    I doubt the ssd is going to fail anytime soon. I personally would make the two ssd drives into fusion.

    You should be ok for cables since you had a fusion drive to start with.
  13. maflynn Moderator


    Staff Member

    May 3, 2009
    Not with a 1TB SSD, I agree. That baby is going to be fast anyways :)
  14. bunger, Oct 30, 2016
    Last edited: Oct 30, 2016

    bunger thread starter macrumors 6502

    Mar 1, 2007
    Just wanted to update:

    I broke the Fusion configuration and replaced the mechanical 1TB HDD with a Samsung Evo 850 1TB SSD drive. I did NOT re-enable Fusion; instead, the Samsung is a standalone drive and the "on-board" 128GB SDD drive is standalone.

    I just ran disk read/write tests against both drives and the results were pretty consistent across multiple tests:

    Samsung: 500MBs read/500MBs write
    "On-Board" SSD: 300MBs read/400MBs write

    I am very pleased with the performance and the test re-affirms my decision to disable Fusion given the faster speed of the new Samsung.

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13 October 23, 2016