Difference between 1TB vs. 3TB Fusion Drive?

Discussion in 'iMac' started by Tofray, Oct 5, 2013.

  1. Tofray macrumors regular

    Mar 7, 2011
    I'm planning to buy a 27" iMac, and am considering the 1TB vs. 3TB Fusion Drive. I use an external drive for media stuff, so I really don't need the 3TB. But $150 is a cheap upgrade for an additional 2TB.

    • Is there any speed differences between 1TB vs 3TB?
    • Are you able to bootcamp a 3TB drive?

  2. iSayuSay macrumors 68040


    Feb 6, 2011
    The difference is 2TB of course .. :p

    In all seriousness, no noticeable speed difference between 1TB and 3TB Fusion because the speed is determined by the SSD rather than the platter.

    It's all about space you need but considering external and NAS is way cheaper nowadays maybe you'd go with 1TB Fusion and use the money toward buying NAS or USB 3 external. IMO $150 is not cheap difference between 1TB and 3TB HDD. It's Apple try to gouge your wallet.

    You can install BootCamp on both but you cannot make use of the SSD for Windows installation. It will be put on HDD and you need to unfusion your drive if you want to manage it manually.

    So if you have the money, I suggest you go with the SSD only option. 256GB might suffice or 512 GB is even better.
  3. Tofray thread starter macrumors regular

    Mar 7, 2011
    Are the read/write & boot speeds much faster for the dedicated SSD vs the fusion drive?

    And thank you much for the great information!
  4. elithrar macrumors 6502


    May 31, 2007
    The dedicated SSD is faster, but the Fusion drive is almost "good enough" that regular tasks are unlikely to see any improvement.
  5. ValSalva macrumors 68040


    Jun 26, 2009
    Burpelson AFB
    I thought there is no difference in speed between Fusion and an SSD for most tasks, especially for booting and commonly used files because the SSD is for all intents and purposes the only drive being accessed.

    It's my understanding that the HDD is used only when manipulating files that are too large for the SSD or for files that have not been used in a significant amount of time and have been moved to the HDD in the background.
  6. MacDarcy macrumors 65816

    Jul 21, 2011
    There is no difference in Reading....but the dedicated SSD is still twice as fast in writing. Booting is equal. At least from the benchmarks I've seen.
  7. roland.g macrumors 603


    Apr 11, 2005
    I'm not sure where you get that. AFAIK the SSD is SSD whether in a Fusion or straight SSD. The only difference in writing will be once the SSD fills and it needs to determine where to write to, which will probably be the HDD, and then it will swap based on rate of access. The SSD performance should still be the same on the new 2013 PCI-e SSDs whether they are stand alone or part of the Fusion drive.

    If you have something that says otherwise, please post a link. I'd be interested to read.
  8. MrGimper macrumors 603


    Sep 22, 2012
    Andover, UK
    You are spot on.
  9. ValSalva macrumors 68040


    Jun 26, 2009
    Burpelson AFB
    This is what I understood too. In a sense the HDD in the Fusion array works in the background. Large files are moved to it (as long as they are not too large and exceed the SSD capacity in which case they access the HDD first) when the OS determines they are not used frequently. It's my understanding that unless one is frequently using multiple large files there is almost no noticeable speed difference between the Fusion drive and just having an SSD.

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