~20% PCIe SSD Slowdown in 10.13.5 vs 10.11

Discussion in 'Mac Pro' started by handheldgames, Jun 7, 2018.

  1. handheldgames macrumors 68000


    Apr 4, 2009
    Pacific NW, USA
    Running updated benchmarks for low level 4k performance, I've discovered an observable slow down in AHCI PCIe SSD performance. Old and new results are shared below... Perhaps the drop in performance is the result of patches for the Specter/Meltdown at the OS level. Unfortunately read and write speed is effected, no both drives tested.

    10/2015 - ElCapitan - combined results 20151tbvs128.png

    6/2018 XP941

    xp941 slowdown.png
    6/2018 Apple 1TB SSUAX
    1tb ssd slowdown.png
  2. Synchro3 macrumors 68000


    Jan 12, 2014
    Cannot confirm a slowdown in 10.13.5 (However, I avoided the APFS format)

    Apple SSUBX

  3. crjackson2134, Jun 7, 2018
    Last edited: Jun 7, 2018
  4. eksu macrumors regular

    Aug 3, 2017
    Can you control more variables before we jump to conclusions? i.e. run the test on the same drives in 10.11 today

    That way you can control for ssd degredation, control for Filesystem (unlabeled in 1st photo) control for how full the drive is, control for cpu microcode, control for other PCIe devices, etc?
  5. bsbeamer macrumors 68000

    Sep 19, 2012
    With APFS on non-Apple issued SSD, I was getting very slow read/write speeds back in 10.13.2 (one of the builds). Changed to HFS+ via Carbon Copy Cloner and all problems went away. I do not recommend APFS for 5,1 with non-Apple issued SSDs.
  6. handheldgames, Jun 8, 2018
    Last edited: Jun 8, 2018

    handheldgames thread starter macrumors 68000


    Apr 4, 2009
    Pacific NW, USA
    Matching up with syncro3's and my legacy results, I forgot to click [x] Allow Asynchronous I/O.

    Booting back into ElCap to verify, read performance on the xp941 looks good. Write performance consistently scales across multiple tests.
    xp941 el cap.png

    Back to High Sierra, read performance looks good but write performance is inconsistent. With the XP941 slowing down faster more times than not.

    xp941 high sierra.png window6-8-1810.52 AM.png window6-8-1810.52 AM-1.png

    Attached Files:

  7. crjackson2134 macrumors 68040


    Mar 6, 2013
    Charlotte, NC
    SSD performance is the same for me as it always has been on my SSUBX. Both file systems yielding same results as when originally installed. I can't remember if it was Cappy, or Yose, but my performance is the same.

Share This Page