Migration Assistant - Ethernet transfer rate slowed right down

Discussion in 'OS X El Capitan (10.11)' started by johngordon, Mar 10, 2016.

  1. johngordon macrumors 68000

    Apr 19, 2004
    I am just transferring stuff from a late 09 iMac to a new one via Gigabit ethernet.

    It started off fairly briskly, at around 45MB/s, estimating around 2.5 hours.

    But it has now slowed right down to about 4MB/s, estimating around 25 hours.

    I don't suppose there's much I can do about it, but any ideas as to what gives?
  2. NoBoMac macrumors 68000

    Jul 1, 2014
    What type of drives are involved? I recall reading an article a few years back where they were testing something similar, transferring data from one machine to another over ethernet. HDD to HDD transfers were about half the rate of SDD to SDD. Also, network interface controllers do affect things (read: not all created equal; not sure what is in current vs old). But that does not match up to what you are seeing.

    Obviously, HDD to HDD will be slow, since spinning platter, moving r/w head, so probably a fair amount of seeking going on. If SSD to SSD, SDD writes do take longer, so, tough time "digesting" what an SSD might be sending over.

    Not sure how Migration Assistant actually does its thing, but, can see where it takes its time re: determine what to move, move it, verify moved ok (at some basic level). So, that will slow things down, plus any other activity that might be going on one of the machines.
  3. johngordon thread starter macrumors 68000

    Apr 19, 2004
    Thanks for the reply - it actually sped up again, so maybe just one of those things.

    It seemed to get stuck near the end, so now have a different issue, so I'll post a new thread.

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