Fusion drive seems slow after High Sierra update

Discussion in 'iMac' started by dimme, Sep 27, 2017.

  1. dimme macrumors 65816

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    SF, CA
    #1
    I have a 2015 27"iMac with the 2TB fusion drive. After updating to High Serra the fusion drive seems slower, Black Magic Speed test also shows a slight slowdown. The drive was not converted to the new file system. It been running a while so I don't think spotlight is indexing. Anyone else notice this?
     
  2. AntnyMikal macrumors regular

    AntnyMikal

    Joined:
    Jun 2, 2012
    #2
    Installed HS yesterday on 5k 1TB fusion. Everything seemed same as always. I was getting the beach ball here and there but I was also running time machine. I’ll be on it quite a bit today so I’ll pay close attention.
     
  3. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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  4. MAJ6288 macrumors newbie

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    #4
  5. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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    #5
  6. MAJ6288 macrumors newbie

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    #6
    As far as I can tell, Apple have said that the FD does not support the new file system. That's not the same saying that high Sierra is not supported.
     
  7. rbart macrumors regular

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    Nov 3, 2013
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    France
    #7
    You are wrong.
    High Sierra supports Fusion drive if you stay with HFS+.
    No performance problem for me (1Tb FD late 2015)
     
  8. JustMartin macrumors 6502a

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    Feb 28, 2012
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    UK
    #8
    If you read the article you cite, it simply states that APFS will not be installed on machines with fusion drives when you install High Sierra. Apple has not advised Fusion users to avoid HS. If Apple didn't want HS to be installed on fusion drives it would have written the installer that way. All that happens is that HFS is left on the drive and HS installed on top of that.

    And breathe. Having said that, while I've not done any speed tests, my machine doesn't feel slower with HS installed, if anything slightly faster.
     
  9. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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    #9
    And when say OS X.13.3 is released and wants to use the new format, could well leave a devil of a mess.

    For mine Apple has a lot of work to do before APFS is properly up and running.
     
  10. PieTunes macrumors 6502

    PieTunes

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    #10
    I’m not sure how waiting for 10.13.x, or whenever APFS is compatible with Fusion drives is released, will be any different for the potential of a “devil of a mess” versus going to High Sierra on an already compatible drive like SSD. When it finally is compatible for HD and FD users the conversion process will be no different then the risk one takes now going from Sierra to High Sierra anyway.
     
  11. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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    #11
    PieTunes I meant if one installed HS on the Fusion Drive now, updating would mean a whole new download, formatting and installing. Folks who had been running Beta on Fusion Drives had to go back to HFS file system.


    https://beta.apple.com/sp/betaprogram/apfsfusion
     
  12. JustMartin macrumors 6502a

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    #12
    'whole new download' - I very much doubt that any upgrade to HS will be anything like the size of the original. It will be a typical .x patch release and installing it won't be a big deal. As for reformatting - that won't be necessary, APFS sits at a layer above the block structure of the disk - SSD users upgrading haven't had deal with a reformat. Yes, the beta users had to go through a number of steps to recover their HFS setup, but that goes with the territory when you beta test. That's why I skipped this particular beta.
     
  13. joema2 macrumors 65816

    joema2

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    Sep 3, 2013
    #13
    You can install HS on a system with FD and it does not require formatting. HS supports FD -- exactly like it supports external spinning drives or drive arrays. All those remain HFS+ so there is no reformatting. Apple has never advised not installing the final shipping version of HS on FD systems. There is a difference between APFS being used on spinning or Fusion Drives vs those drive types not being supported by High Sierra. Those ARE supported by High Sierra but APFS does not yet support non-SSD drives in the shipping HS version.

    Whenever APFS supports non-SSD drives, that will require reformatting but not reloading all your data. Just like when HS reformats SSD drives as APFS, this happens transparently.
     
  14. theluggage macrumors 68040

    Joined:
    Jul 29, 2011
    #14
    I'd give it a chance to "run in" before jumping to conclusions. Also, Its not uncommon for a Mac to run like treacle for a while after a major OS change, especially if there's a lot of stuff on disc: All the spotlight indices will have to be re-built, Photos might want to re-do face/location ID on all of your pictures etc. The fusion drive might take a while to make sure that all of the commonly accessed files (many of which will be changed by the upgrade) are on the SSD portion. The SSD has probably got an epic garbage collection job on its hands getting rid of all the old data, too.
     
  15. drowsier macrumors newbie

    drowsier

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    Oct 4, 2017
    #15
    What kind of numbers are you seeing with Black Magic?

    I've got the late 2015 27" iMac with 3.1TB Fusion Drive. I didn't install any of the betas but I did install the release High Sierra -- about 3 days ago. My whole computer feels really slow, so I finally ran some disk speed tests. I ran black magic but don't remember what it had previously. Also ran AJA with the 16 GB test file size, and it's showing 93 MB/sec write and 76 MB/sec read -- very terrible.

    DiskMark 1.15 shows Sequential read/write at 290/708 MB/s, and Random at a horrible 0.4 MB/s read and 0.3 MB/s write.
     
  16. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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    #16
    Maybe so JustMartin but for guys who wait until the FD version is released , IT WILL be the whole complete download for them and from what I read also for those who ran HS via HFS and want to get the APFS version for FD.
     
  17. AntnyMikal macrumors regular

    AntnyMikal

    Joined:
    Jun 2, 2012
    #17
    I’ve been running mine since late beta and official release. It’s the same as it’s always been up to this point. I checked to make sure that I still had HFS which I do. I’ll probably installing the beta update tomorrow after checking out the details and doing a back up.
     
  18. AL2TEACH macrumors 6502

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    Feb 17, 2007
    Location:
    Denver, CO.
    #18
    I would suggest downloading EtreCheck, run it and pay attention to anything in red.
    https://etrecheck.com/
     

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