Will downloading things to second HDD still write to my main SSD

Discussion in 'MacBook Pro' started by abcdefg12345, Jun 14, 2014.

  1. abcdefg12345 macrumors 6502


    Jul 10, 2013
    I have a macbook pro with 120gb SSD in main drive and 1tb HDD on optical drive place and I'm wondering will utorrent still wear out the SSD if I'm using it to download directly to the HDD

    like would it still write data to the SSD wear it out while downloading to the HDD is it better to boot into the HDD and eject the SSD when downloading to prevent any extra writes to the SSD

    I'm currently triple booting main mac os on SSD and windows 8.1 and os x Yosemite on the HDD
  2. snaky69 macrumors 603

    Mar 14, 2008
    No. If your download folder is on the HD, then that's where it's writing.
  3. abcdefg12345 thread starter macrumors 6502


    Jul 10, 2013
    i was downloading a few movies today and i had my downloads folder set on the HDD and according to Activity Monitor i still got too much data written into my SSD

    is that normal
    Screen Shot 2014-06-21 at 8.32.34 pm.png

    i think i'm better off booting into the HDD while downloading instead of the SSD
  4. alex0002 macrumors 6502

    Jun 19, 2013
    New Zealand
    I don't see anything there that states that data was written to the SSD.
  5. abcdefg12345 thread starter macrumors 6502


    Jul 10, 2013
    so does activity monitor show data written in general to all drives or only the one you booted into, i always thought it shows the one u booted into
  6. alex0002 macrumors 6502

    Jun 19, 2013
    New Zealand
    I thought it would be all, but the best was to find the answer would be to run isostat in a terminal while you do your downloads.

    $ iostat 10 5
              disk0       cpu     load average
        KB/t tps  MB/s  us sy id   1m   5m   15m
       54.74   2  0.10   6  2 92  1.24 1.19 1.21
       85.12   5  0.42   1  1 98  1.27 1.20 1.21
        4.00   0  0.00   2  1 97  1.24 1.20 1.21
       25.39   2  0.04   0  1 99  1.12 1.17 1.20
      326.00   0  0.13   3  2 95  1.18 1.18 1.20
    The command line above checks every 10 seconds and stops after 5 samples. You can monitor for a longer period if you wish. When I plug a USB drive into my MBP, I get stats for disk0 and disk1, so you should be able to see both drives. Note the first row of data gives the stats since the last boot.

    However, while you download to the second drive, there will be some writing to log files, some writing due to spotlight and perhaps some paging/swap activity, so you should always expect some writing to the boot drive.
  7. joe-h2o macrumors 6502a

    Jun 24, 2012
    If the SSD is your boot drive then it will always seem some traffic while the computer is running.

    I'm not sure what you mean by "wearing out" though - are you concerned your SSD will die due to exhausted write cycles?

    That's simply not going to happen to a modern SSD with the sort of use you're talking about.

    Heavy benchmark and cycle test suites that put terabytes of data through SSDs have demonstrated that throwing hundreds of gigs per day of writes would still take years to wear the drive out.

    TL;DR: treat it as a normal drive.
  8. SVTmaniac macrumors 6502

    Jan 30, 2013
    I can't help but laugh at people who think they are going to wear their SSD out in a home use situation. Maybe if you constantly read and write to it 24/7 over a 10 year period.. maybe, but it's just not gonna happen. You're computer will need replaced due to old age long before you can wear that SSD out.
  9. glenthompson macrumors 68000


    Apr 27, 2011
    I just checked the wear statistics on my Samsung 840 Pro that I installed over a years go. At my current rate of usage, I will wear it out in 112 years. My wife's iMac only has about 8 months on her SSD but it shows the same wear stats. Even if I increase my usage by an order of magnitude that still nets me over 10 years. I think I'll replace the MBP before then.

    Quit worrying about wearing out your SSD. You will want to upgrade to a larger one before it gas a problem.

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