5400rpm Fusion Drive, or External USB 3?

Discussion in 'iMac' started by G.McGilli, Oct 19, 2015.

  1. G.McGilli macrumors regular

    Oct 19, 2015
    Hey All!

    I'm trying to decide.

    A 3TB Fusion drive - or 256gb SSD and then use External USB3 HDD.

    In the end - both will come out costing about the same.

    While I do Photoshop work, as well as a tonne of audio production - most everything else is on external drives right now on a 2011 Mac Mini with a 5400rpm 512gb drive (that's only 1/2 full - and I have 2TB on external drive)


  2. snow755 macrumors 65816


    Sep 12, 2012
    get Fusion drive 100% it may coast you more $ but it be well worth it do not get any thing with a HDD turst me you be wanting too return it so save your self some time and get the Fusion drive and you will be a vary happy camper on day 1
  3. G.McGilli thread starter macrumors regular

    Oct 19, 2015
    Thanks for that.

    Ooops I didn't realize that the Fusion Drive is 7200rpm... Hmmm yeah going that way may just be the best then....
  4. Textureboy macrumors 6502


    Jul 25, 2012
    Definitely don't get the standard HDD. If you've never used an SSD before the fusion drive would be great for you.

    I went to the store today and tried on the fusion drive iMac and I was disappointed in its performance as I did find it to stutter on occasions.

    I've been using my first generation Retina Macbook with 512SSD and I did consider the 3TB fusion drive because of the extra space. But after testing out the 2TB fusion drive in store I'm definitely going to stick with SSD. Not to say that the fusion drive is slow at all.
  5. Wallabe macrumors 6502a

    Mar 15, 2015
    Once you go SSD, you don't want to go back to RPM drives, including fusion, especially for an internal/main drive. Spend the money on SSD and buy an external drive. You have to use the iMac sitting at a table anyway.
  6. Spink10 Suspended


    Nov 3, 2011
  7. ApfelKuchen macrumors 68030

    Aug 28, 2012
    Between the coasts
    The point (to me) of Fusion is that it is self-managing. Whatever benefits from being on SSD is present in SSD. Just those parts of the OS and apps that you actually use, plus whatever data you happen to be working with.

    For my money, placing the entire OS and all your apps on SSD is a waste of expensive space - much of that code will rarely, if ever, be used, and certainly not concurrently. And since you can't fit all your data onto the SSD, you're left manually transferring data from and to the HDD - not exactly an efficient use of time.

    Who cares if it's a 5400 RPM or 7200 RPM HDD? The Fusion setup minimizes the impact. Fusion consistently benchmarks at 80-90% the speed of pure SSD - with a 5400 RPM drive. Any benefit you might get from a somewhat faster external HDD is likely to be lost to the inefficiencies of operating without active Fusion management.
  8. Chupa Chupa macrumors G5

    Chupa Chupa

    Jul 16, 2002
    Might be true with the older 1TB Fusion Drive with the 128GB SSD but the new ones have just 24GB. I have my doubts that they are going to benchmark in real use same as the older model.
  9. ixxx69 macrumors 65816

    Jul 31, 2009
    United States
    The Fusion Drive can be a fine choice for some, and for some users, the idea of having to deal with more than one "drive" is just too confusing to make up for the performance differences. But you're making it sound way more time consuming management involvement there is.

    For most users who need more than 250GB of drive space, it's because they have a huge library of something... a photo library, iTunes library, or video editing, etc., and in those scenarios that cover 90% of users who need more than 250GB, it's very easy to keep those on a separate drive - it's pretty much self-managing through the software.

    Meanwhile, having the entire OS and all your apps on an SSD is the single most significant performance boost you can give a computer.

    It's unfortunate the whole Fusion Drive offers "80-90% the speed of a pure SSD" has spread around these forums, because it's a gross over-simplification of the trade off. The issue is that when the SSD portion of a fusion drive is working in your favor, it offers 100% of "pure" SSD performance... but when it's not, it's offers 0% of "pure" SSD performance. So what "80-90%" really means is that if you're a "typical" user, you're getting SSD performance 80-90% of the time... and the other 10-20% of the time you're getting HDD performance (which is even worse when it's a 5.4K drive). That may be perfectly acceptable to a lot of users.
  10. netnothing macrumors 68040


    Mar 13, 2007
    Just another perspective......I am against any traditional spinning drive inside I computer that I can't service myself. Spinning hard drives fail. I don't want to have to deal with Apple just to get that fixed. If I were you I'd do pure SSD internally, and supplement with either USB3 or Thunderbolt externally that you can easily replace if the drive fails.

  11. G.McGilli thread starter macrumors regular

    Oct 19, 2015
    Thanks everyone.

    Yeah I've been using SSD in my MB Air and MB Pro Since 2009 and I agree it's hard to go back to HDD. However as stated in my first post my daily driver is a Mac Mini that's dragging down my work lately - so was looking for some suggestions, and got them :) Great input, helps me decide that I'm done with HDD. Fusion might work if it had 256gb SSD but even then - I prefer external drives - way easier to switch computers and have all your data ready to go.

  12. maflynn Moderator


    Staff Member

    May 3, 2009
    Agreed, after the OS occupies its portion of the flash drive, there's not much else for your data to be on the flash drive. I think overall user experience with the new 1TB Fusion drive will be less then the older one.

    That's my recommendation as well. Apple however charges a lot of money for the SSD upgrade but from what I hear opening up the iMac can be a real pain.
  13. roadkill401 macrumors 6502


    Jan 11, 2015
    There has been many a war or so it came across about the fusion drive on this forum.

    To understand if the fusion is right for you, you have to understand how it works. It is a system that moves the most accessed data from the hard drive that is slow to an SSD that is fast. The SSD is not the biggest so it CANNOT hold everything and there is a certain amount of latency involved with moving items on and off the SSD to the harddrive. Now most of this will happen in the background during cycles that you are not using the machine. Depending on how much data you have and the type of access your workload generates may or may not work well with the Fusion. The fusion is not controlled by you and you don't get to decide what you feel is important to have on the SSD portion or not.

    For example:

    As the fusion drive knows you access OSX all the time, this is loaded into the SSD, along with your web browser cache that get accessed a lot, perhaps as you listen to iTunes, it puts it's catalog on the SSD... etc.

    For work you have a large array of audio files (>128gb) that you access on a sporadic basis. The fusion drive cannot know what files you will want next so they will not get loaded onto the SSD and the transfer rate to load is limited by the RMP speed of the physical hard drive. I have not seen anywhere Apple stating that the 3TB fusion drive uses 7200rpm drives. So in this case, an external 7200 drive would be faster.

    However, you also have a bunch of templates that you use on a consistent basis for work. Now the fusion knows these get accessed all the time, so it will move these files over to the SSD portion of the fusion and you are getting these files at the SSD drive speed that will be faster than an external drive.

    A Fusion drive will always be faster to save your work to than an external drive as it will automatically pre-cache the written data to the SSD than an external USB3 or Thunderbolt drive.

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12 October 19, 2015