Fusion Drive Start/stops

Discussion in 'iMac' started by Suffa, May 27, 2013.

  1. macrumors member

    Joined:
    May 11, 2013
    #1
    I've come across something strange. When I download something with utorrent, it first downloads at full speed, but quick after the speed goes down to 0 and I can see that the SSD is reading something at 30 MBps, and then it starts with full speed again for a couple of seconds before it stops again.

    What can the problem be? Isn't fusion drive able to keep up?
     
  2. macrumors 68040

    Joined:
    Jul 11, 2009
    #2
    That's not the fusion drive. Any regular disk can keep up with internet bandwidth.
     
  3. thread starter macrumors member

    Joined:
    May 11, 2013
    #3
    I wonder what the problem is then. Seems like the SSD is moving data to the HDD and thats why the writing stops during transfer. Weird.
     
  4. macrumors G5

    gnasher729

    Joined:
    Nov 25, 2005
    #4
    The opposite. Your download stalls for a bit, so the fusion drive says "this is a good opportunity to copy some stuff to the hard drive while I'm not busy".
     
  5. thread starter macrumors member

    Joined:
    May 11, 2013
    #5
    But it doesnt look like it stalls, it goes full speed, and then down to 0, and when it does that i can see that the SSD is reading/writing data, and when that is done, the download goes full speed again..
     
  6. macrumors G3

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    Location:
    Sol III - Terra
    #6
    Try a large direct download from somewhere if you really want to test. Torrents have so many factors affecting performance, it's difficult to say where the issue is.
     
  7. macrumors 6502

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    Jan 18, 2013
    Location:
    Columbia, SC
    #7
    A SLOW HDD can transfer data at ~100 megaBYTES per second. A FAST home internet connection can transfer data at 100 mega BITS per second, or roughly, 1/10th as fast. As has been said before, the Fusion drive is not the issue, it's your internet connection.
     
  8. thread starter macrumors member

    Joined:
    May 11, 2013
    #8
    No its not the connection, its not a problem when using windows.

    So its just a big coincidence that the fusion drive starts working with something as the speed go down, and when it stops the download continues?
     
  9. macrumors 68000

    Joined:
    Jan 26, 2008
    #9
    Does this happen on other downloads (non-torrent)? It's highly doubtful the Fusion drive is causing this problem. The internet in general isn't perfect. Torrents are especially unpredictable.
     
  10. macrumors 6502

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    #10
    My guess is the OS X torrent client is having issues.

    Since even an older/slower HDD is easily 10 times faster than a normal (U.S.) internet connection, I just don't see the Fusion drive being the issue.

    Point the torrent download to an external HDD or even a USB flash drive. At least that way you can prove one way or the other that it's related to the Fusion drive.
     
  11. Suffa, Jun 13, 2013
    Last edited: Jun 13, 2013

    thread starter macrumors member

    Joined:
    May 11, 2013
    #11
    I just think it's weird that as soon as the SSD starts reading at 30 MB/s, all downloads stop. And when it stops reading, the download continues.

    http://i177.photobucket.com/albums/w236/fredio/Skaumlrmavbild2013-06-13kl113428_zps05668329.png

    Seems like the fusion drive is doing something, and can't write data until it's done. But i dont understand what it is doing, if it was moving files, it would be writing data, now its just reading, nothing else and no activity on the HDD.
     
  12. macrumors 68040

    Joined:
    Jul 11, 2009
    #12
    If you have only 79GB on your Fusion drive, ALL of your data resides on the SSD, so there is no file moving going on.
    What app shows the information in your screen capture?
     
  13. thread starter macrumors member

    Joined:
    May 11, 2013
    #13
    I dont think the program is showing incorrect information, it does everything else perfectly.

    It's iStat Menus 4
     
  14. macrumors 6502

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    Columbia, SC
    #14
    Have you tried the suggestion of having the torrent download onto an external drive?
     
  15. thread starter macrumors member

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    May 11, 2013
    #15
    Do you think it's bad to use utorrent with Fusion Drive? Or shouldn't that be a problem?
     
  16. macrumors 6502

    Joined:
    Jan 18, 2013
    Location:
    Columbia, SC
    #16
    Unless your machine is broken, Fusion isn't the issue. Once again, have you tried the option of telling uTorrent to download to an external drive? Tell it to download to a flash drive, or even an external hard drive. See if the problem continues when you download to something OTHER than the Fusion drive. It's basic problem solving... if uTorrent has no problem downloading to a drive other than your Fusion drive, your Fusion drive has a problem with it. If uTorrent does the same thing (start/stop) then it's a uTorrent problem.
     
  17. macrumors 68000

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    Dec 8, 2009
    Location:
    Sydney, Australia
    #17
    I use uTorrent with the fusion drive in my iMac and i have no such issue. I use a private tracker so my speeds are stable (i leave utorrent on 24/7) and very very fast :) The issue would be the utorrent setup or the tracker you are using.
     
  18. thread starter macrumors member

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    May 11, 2013
    #18
    Is it ok to torrent on a SSD? Isn't that very damaging?
     
  19. macrumors G5

    gnasher729

    Joined:
    Nov 25, 2005
    #19
    You may make sure that you don't try do download illegal copies of Mac software, because that's the surest way of getting a trojan that messes your Mac up. And there are plenty of torrents for downloading illegal copies of music / videos / books etc., which is very damaging to the artists and may be damaging to you if you are caught.

    But what makes you think that using an SSD drive would make any difference?

    Nuke61 gave you the basic options of problem solving - if A and B together causes a problem, try to change either A or B and see if the problem stays or goes away.
     
  20. thread starter macrumors member

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    May 11, 2013
    #20
    Yea im not here to talk about downloading copyrighted content. Torrenting is not only for illegal downloads.

    And since your answer is like that you probably have no clue what you're talking about.
     
  21. macrumors 6502a

    Joined:
    Mar 27, 2010
    #21
    Are you talking about the write limit on an SSD being smaller than that on a traditional hard drive?
    If you are then there's little to worry about. It is true that SSD's have a more limited write limit, if you torrent normally (20-40GB a month), the other components of your computer will most likely go before your SSD does; heck your HD will probably go before your SSD. Just remember to backup daily.

    Normal consumers like you or I don't need to worry about SSD write limits, it's mainly large companies with stacks of SSDs using them 24 / 7 writing loads and loads of small files to the SSD.

    If you're torrenting 15-20GB a day, then it might be better practice to save it to a traditional hard drive then copy the whole file over when it's done.
     
  22. thread starter macrumors member

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    May 11, 2013
    #22
    Thank you for that answer, i appreciate it a lot! :)
     

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