Why does write/read speeds drop drastically?

Discussion in 'iMac' started by gr8pics, Apr 27, 2017.

  1. gr8pics macrumors regular


    Jan 20, 2008
    I got a imac 27 late 2015, got a 2TB fusion drive, 1.5TB free space.
    Using Disk speed test, loading file 5gb, and runs continuously, it shows 600/1500 once or twice, but 9 out of 10 times it slows down to 160/160
    Can someone explain why?Im running the test from the root of user folder.

    OSX 10.12.4
    --- Post Merged, Apr 27, 2017 ---
    Can moderator please delete the 2 most recent duplicates of this post?
  2. shaunp macrumors 68000

    Nov 5, 2010
    At a guess I'd say it slows down as it needs to move stuff from SSD to HDD as part of the fusion process.

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