Late 2015 iMac SSD Benchmarks

Discussion in 'iMac' started by Lessig, Mar 2, 2018.

?

You're right, that's way below spec.

  1. Yes

    75.0%
  2. No

    25.0%
  1. Lessig macrumors newbie

    Lessig

    Joined:
    Sep 21, 2017
    Location:
    Brookline, MA
    #1
    I'm convinced by late 2015 iMac disk is radically under-performing. I've found lots of cool tools for measuring the speed, but nothing that gives me a clear benchmark about what I should expect. Can anyone help? (Blackmagic run at 5GB) DiskSpeedTest.png Screen Shot 2018-03-02 at 11.06.22 AM.png
     
  2. MadDane macrumors 6502a

    Joined:
    Apr 5, 2015
    #2
    What storage do you have? Fusion Drive or full SSD?
     
  3. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #3
    Something is just not right. Dug out my late 2013 i7 3TB Fusion and booted it up.

    Black Magic shows Write 320MB/s and Read 688MB/s so Write is way down.
     
  4. Lessig thread starter macrumors newbie

    Lessig

    Joined:
    Sep 21, 2017
    Location:
    Brookline, MA
    #4
    Fusion
    --- Post Merged, Mar 3, 2018 ---
    What should it be?
     
  5. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #5
    How full is the PCI-e blade drive? Maybe it is writing to the slow old platter drive.
     
  6. MadDane macrumors 6502a

    Joined:
    Apr 5, 2015
    #6
    It looks like SSD read speeds and HDD write speeds. Since it is a Fusion Drive it seems reasonable.
     
  7. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #7
    No it is not.

    See the BM on my Fusion. 320MB/s compared to Lessig's 117MB/s.
     
  8. MadDane macrumors 6502a

    Joined:
    Apr 5, 2015
    #8
    I just dug around on the Internet a bit more. It would seem that the 6xx/3xx read/write speeds are the norm. So I would say that nambuccaheadsau is right. Your write speed looks too low.
     
  9. RyanXM macrumors 6502

    RyanXM

    Joined:
    Jul 7, 2012
    Location:
    DFW, TX
    #9
    The 21.5" iMac with HDD or Fusion HD, both use a 2.5" 5400RPM drive. That write speed is in line with the latest 2.5" 1TB or 2TB HDDs.
     
  10. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #10
    With only 24GB of SSD it is not unnatural the platter drive write figure is shown I guess.
     
  11. Lessig thread starter macrumors newbie

    Lessig

    Joined:
    Sep 21, 2017
    Location:
    Brookline, MA
    #11
    Wow, you all worked hard this weekend! <gratitude> I'm at 70% capacity utilization.
     

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10 March 2, 2018