Fusion Drive 5400 or 7200 rpm?

Discussion in 'iMac' started by vmd, Nov 30, 2012.

  1. vmd macrumors newbie

    Sep 19, 2012
    Dear all,

    I am still hesitating between a 21,5 or 27 inch. If I take the fusion drive on the 21,5 will it be a 5400 or 7200rpm hard drive ?

    Thanks !
  2. WilliamG macrumors G3

    Mar 29, 2008
    Very good question. I'm also wondering if the 3TB Fusion drive is a 5400rpm or a 7200rpm disk.
  3. darkanddivine macrumors member

    Jan 13, 2007
    Just asked this question in the buyers guide section too.
  4. vmd thread starter macrumors newbie

    Sep 19, 2012
  5. darkanddivine macrumors member

    Jan 13, 2007
    Hahah! Well that's erm... interesting. Thing is, for me, my decision rests pretty much on that spec. We know the fusion is fast, but for me I might use a non-fusion and wait for the 27" if the 21" one turns out to be less effective. My choice is between less RAM & fusion, or more RAM and no fusion.
  6. tann macrumors 68000

    Apr 15, 2010
    Nottingham, England
    I am assuming (for now) fusion is simply the 128gb flash memory + whatever the default hard drive is...
  7. throAU macrumors 603


    Feb 13, 2012
    Perth, Western Australia
    Most of the larger drives on the market are 5400 rpm.

    Also, the fusion drive is probably 5400rpm to save power - it seems to be the default option apple use.

    I don't know for sure, this is just speculation, but....

    I doubt that the rpm difference will make much real world difference anyway, 128gb of cache is HEAPS for caching hot data, all writes are cached and serialized in SSD first, so they only time the rpm difference will make any real performance impact is if you are performing a lot of random reads on non-sequential data, that you don't frequently access, and were written a long time ago.

    Yes, of course in theory a 7200 rpm drive would be better, but real world performance difference? I doubt you'd be able to measure it unless running a very specific benchmark to attempt to provide a worst case scenario to the setup.

    Given the above - i doubt apple would pay the extra $ and power/heat for a 7200 rpm drive.
  8. vmd thread starter macrumors newbie

    Sep 19, 2012
    I don't know for sure but I am thinking like tann
  9. xgman macrumors 601


    Aug 6, 2007
    If all the standard drives in the 27" are already 7200, why would they down speed the fusion to what the 21" comes with?
  10. The Phazer macrumors 68030

    Oct 31, 2007
    London, UK
    I think that's unlikely. Likewise, the 21" probably has to use a 5400 due to heat. So the fusion drives probably use the same speed as regular drives on that system.
  11. rnb2 macrumors regular

    Jan 23, 2006
    West Haven, CT, USA
    The 21.5" has a 2.5" hard drive - 5400rpm 1TB 2.5" drives have very high data density per platter, so the speed difference shouldn't be significant compared to a 1TB 3.5" 7200rpm drive.
  12. azentropy macrumors 68020


    Jul 19, 2002
    If it is the same 2.5" that is in the Mac mini it is a dog. I don't even get 100MB/sec read or write on it vs. 400MB/sec on a SSD and ~160MB/sec on an external USB 3.0 3TB drive.
  13. torana355 macrumors 68030

    Dec 8, 2009
    Sydney, Australia
    Fusion drive only uses 4gb for "caching" hot data" If you copy a file larger then 4gb you may notice the performance decrease as it starts to write to the regular hdd or offload data from the 4gb ssd cache to the hdd. In practice 4gb's is actually a very large amount and most users should not be able to tell the difference in everyday usage.
  14. rnb2 macrumors regular

    Jan 23, 2006
    West Haven, CT, USA
    Totally untrue - the Fusion Drive always holds 4GB in reserve on the SSD for performance reasons (SSDs don't like to be completely full). You seem to have confused this with caching, but Fusion Drive isn't really a caching system, regardless. All writes go to the SSD and are then moved to the HDD if they aren't accessed frequently. In practice, you can write data to the Fusion Drive at SSD speeds until it fills up; not sure if it stops 4GB short of completely full, or more than that - Macworld did a test on the mini that says "up to 100GB", but that seems to be data on top of the standard OS + Apps install.
  15. torana355, Nov 30, 2012
    Last edited: Nov 30, 2012

    torana355 macrumors 68030

    Dec 8, 2009
    Sydney, Australia
    I know that hence me putting caching in quotation marks, though it does use the 4GB for a writing cache of sorts ;) The thing is you will still take hits in write performance when writing large files (files larger then 4GBs) as you start having to offload data that is being written to the SSD to the HDD as the SSD only keeps 4GB's free. Anything under 4GBs should perform the same as a regular SSD drive.

    Most of the downfalls of fusion are in the reading of files that are allocated to the HDD portion of the FD, if the system works as Apples says it does the files read of the HDD should not be files we access regularly although they could still be files that could benefit from SSD speeds, moreso then a few media files that i may access all the time that the FD decides should go on the SSD.
  16. throAU macrumors 603


    Feb 13, 2012
    Perth, Western Australia
    People are getting hung up on how i used the word cache.

    Yes, it uses 4gb to cache writes.

    The rest is used for hot data. Not exactly as a cache, but permanent storage for hot data. Not caching exactly, but as far as speed goes the end result is the same.

    Either way, end result is whether the drive is 5400 or 7200 rpm, 90% plus of your access will be to the SSD part, so the (say) 10% speed difference or so between 5400 and 7200 when you hit the HD 10% of the time is going to have 1% impact to your day to day usage, tops.

    I guess what i'm saying is that it doesn't matter much. Maybe apple want to standardize on 7200 rpm drives, maybe they want to be cheaper and use 5400. Performance for the end user isn't going to be much different in actual use.
  17. Geeks On Hugs, Dec 5, 2012
    Last edited: Dec 5, 2012

    Geeks On Hugs macrumors newbie

    Dec 5, 2012
    San Francisco
    It is 5400rpm

    According to this site:


    The mechanical portion is 5400 RPM.

    Personally I think the Fusion drive sounds cool but as someone who prefers 100% SSD I am very disappointed in the outrageous pricing for a full SSD option.

    This will be my first Mac (for my own computer). I recently started a new job (I'm an Android developer) and was issued a MacBook Air for my work computer and fell in love with OSX (the *nix command line sealed the deal). My previous home/work computer has been running Ubuntu with SSD and I of course my MacBook Air is SSD and now I have to go back to mechanical. There's no way I can justify spending $1 more than the base iMac itself for an SSD.

    Basically I could upgrade to SSD or BUY A SECOND iMAC!! That's crazy.

    I probably won't even bother with the Fusion. I want a 27" iMac and as soon as I can get it from my local Apple store I'm gonna get it. Can't wait for it to be ordered! :p At least the 27" has a 7200 RPM drive. If they take too long on the 27" ima break down and get a 21.5". I'm bad waiting for new toys once I've made my decision. :p
  18. MeFromHere macrumors 6502

    Oct 11, 2012
    Macworld was testing the fusion drive in a Mac Mini. Mac Mini uses 5400 RPM HDDs, so it's no surprise that the fusion drive uses the same.

    The unknown is the fusion drive in the 27" iMac. This system uses 7200 RPM HDDs, and it would be perfectly reasonable to stay with 7200 RPM for fusion in this system. Or they could go cheaper/cooler/quieter with 5400 RPM.
  19. obsoletepower macrumors regular

    Dec 14, 2006
    Toronto, Canada
    Heh if they put a 5400 RPM drive in my 27" fusion setup I will spit in their face! There should be an option to have the mechanical drive be a thunderbolt external to minimize internal heat even more.
  20. mchoffa macrumors 6502a

    Jul 12, 2008
    Asheville, NC
    I'd much rather buy a macbook air than pay $1300 for a faster (and smaller) drive
  21. unknownx macrumors regular

    Oct 25, 2011
    How come we cant know more specific whats in iMac ?
    Why dont they have a full specification?

    Do we really need to spend alot of money and open it ourself to find out what we bought ?

    I would really want to know if its a 5400 or a 7200rpm on the 27".

    Being a 5400rpm we would spend way more whats it worth for a 128gb ssd
  22. hfg macrumors 68040


    Dec 1, 2006
    Cedar Rapids, IA. USA
    From their online specs:

    1TB (7200-rpm) hard drive

    Configurable to 3TB hard drive, 1TB or 3TB Fusion Drive, or 768GB of flash storage.

  23. Curren~Sea macrumors regular


    Jun 21, 2006
    Vancouver, BC
    For what it's worth, I just called Apple and they confirmed to me that the hard drive portion of the Fusion Drive on the 27" iMac is 7200 rpm.
  24. iLondoner macrumors 6502


    All 21-in models have a 2.5-in 5400rpm 1TB HDD, all 27-in models (except the SSD-only version) have a 3.5-in 7200rpm HDD that is either 1TB or 3TB.

    All models except the low-end 21-in have a blade slot for the SSD component of the Fusion drive.
  25. Laucian Nailor macrumors member

    Laucian Nailor

    Oct 24, 2012
    This ^

    Fusion is only a single drive in software, not hardware. Simplified, the SSD component is simply added to the machine, the existing hard drive remains. If it had a 5400 drive already standard (21.5") then that is the speed of that element of the fusion drive (so 7200 for the 27" model).

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