fusion drive...

Discussion in 'iMac' started by Damian83, May 31, 2016.

  1. Damian83 macrumors member

    Jul 20, 2011
    hi i have an imac 27 with standard 1tb hdd. i use an external thunderbolt ssd with osx on it and the 1tb hdd as additional space. today i got the new 27 retina with 2tb fusion drive in it. ill still use the thunderbolt ssd as primary drive as i often switch it to macbook air. what will happen if i format the fusion drive?? it will still be seen by os as an 2tb drive or ill have twho separate drives (ssd+hd)???
  2. dimme macrumors 68000

    Feb 14, 2007
    SF, CA
    You can format the fusion drive and it will act like any other drive and it will still be "fused", You can also "de-fuse the drive and have two separate drives. The SSD & HD.
    Are you saying you use the same SSD to boot the MBA and the iMac. Although that may work, it may not be the best long term strategy.
  3. ivanwi11iams Contributor


    Nov 30, 2014
    Somewhere on Earth
    I'd like to know, too...
    Curious, with your external SSD drive, have you ran the Blackmagic hard drive speed test? If so, is it really faster than the 2TB fusion drive? Thanks
  4. rbart macrumors 6502


    Nov 3, 2013
    It's a strange setup.
    You iMac will be faster if you boot on the internal Fusion drive.
    You external TB SSD is slower than the internal PPCIe SSD.
    But you can format it, and use it as FD or you can split the 2 drives with some command lines.
  5. Easttime macrumors 6502a

    Jun 17, 2015
    I thought that a bootable drive set up for one Mac should not be used to boot another Mac owing to different system configurations (drivers and the like)?
  6. Damian83 thread starter macrumors member

    Jul 20, 2011
    i dont care about speed. its 300mb/s and its enough. the fact i can use same configuration also with my macbook air, or any other macs (i travel very often) its a must for me, and maybe the best thing osx can offer, compared to any other OS.
    ok so i leave the FD "fused" then.
    PS: the only problem with the external ssd its the seagate enclosure thats limited to sataI. i have to search for a sataII in order to reach the max speed
  7. varian55zx macrumors 6502a


    May 10, 2012
    San Francisco
    I unfused mine tonight and I so far am heavily in favor of having done so.

    There's never any question as to what I want on either drive, so I don't need a computer to do it for me.

    Managing files on a relatively light level is somewhat of a hobby of mine, anyway, so that, if anything, is a plus.

    The whole point in me buying the 2tb fusion was to avoid the use of an external drive, and I can still do so.

    Now I have a drive that is just as fast in terms of read speed as the 256 SSD and a 2 tb internal allowing me to avoid external drives.

    Much better for me.
  8. Fishrrman macrumors P6


    Feb 20, 2009
    Damian wrote:
    "i dont care about speed. its 300mb/s and its enough"

    That's what they all say.... ;)

    The internal PCI-e based SSD in the new iMacs will run 3x to 4x faster than a plugged-in booter (and I'm an advocate of "external booters" in this forum).
    The difference will be quite noticeable.

    But something more important:
    I'm not sure if your best approach is to use a single external booter on both the new iMac and the MacBook.

    I just believe it's better to set up each to "be its own Mac", so to speak.

    Of course you want to share stuff between them, such as data.

    Easily done with your portable drive.

    But for the OS, let each Mac "be its own booter".

    If something goes wrong with your thunderbolt drive, you've lost it all.

    But with each Mac running independently (with backups, of course), there's a much greater probability that your DATA will "live on" ...
  9. ivanwi11iams Contributor


    Nov 30, 2014
    Somewhere on Earth
    ...some very valid points here!

  10. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    That is not a problem. All the needed drivers are included with every install, so as long as both Macs are capable of running that OS version, you can swap back and forth no problem.
  11. Easttime macrumors 6502a

    Jun 17, 2015
    Now I really wish my Macs had USB3!
  12. Damian83 thread starter macrumors member

    Jul 20, 2011
    i use this configuration from maybe 5 years, never had problems, and im a really happy mac user. now i have to dont use it anymore because someone on a forum told me im doing in wrong way? ahahhahha. and for what? for gaining 3s on boot time? please...

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11 May 31, 2016