Problem with Fusion Drive's SSD?

Discussion in 'iMac' started by GRBaset, Mar 19, 2018.

  1. GRBaset macrumors newbie

    Joined:
    Mar 19, 2018
    Location:
    The Universe
    #1
    Hi, I'm new here. I'm currently worried about my Late 2015 iMac's Fusion Drive's SSD, as you can probably see in my status. The problem is that just a bit after 2 years I downloaded DriveDx and the Wear Leveling Count is at 52 % already! It came down from 53 % yesterday. And I can see more than 50 TB have been written! My suspicion is that macOS uses the SSD for paging. Even though I have 16 GB of RAM, there's still 3.19 GB currently paged (I'm a very heavy RAM user, I use Chrome because I need the extensions, which use a lot of RAM, and I sometimes boot a 3 GB W10 VM). Is that the reason? Would you recommend moving the paging to the HDD? If so, how? I found how to disable it, but not how to move it. Or should I worry less about that? What would be the cost of a repair if needed? I've seen figures of 700 €, which is a lot of money, so I'm very worried. Ah, and there's another problem: the UDMA CRC Error Count is very high (63) and is getting higher. This happened today! I understand this isn't the SSD's fault, but a connection or power supply fault. Finally, I attach a screenshot of the DriveDx window. Captura de pantalla 2018-03-19 a las 12.40.54.png
     
  2. Samuelsan2001 macrumors 604

    Joined:
    Oct 24, 2013
    #2
    Modern SSD's will write petabytes of data before showing any issues 50TB is fine and all those indicators look just fine, delete the app and worry less would be my advice.
     
  3. vkd macrumors 6502a

    vkd

    Joined:
    Sep 10, 2012
    #3
    I've got double the Power On Hours to you, at 19,000 actually, and a Power Cycle Count of just 1,287, whilst yours is 12,000. This means that you've used your computer less but turned it on and off much more. As you can see that has brought your Power Cycle Count status down to 85%. My Power On Hours is at 79% so lost in comparison but for a far greater time. My Wear Levelling Count is at 74 with a status of 74% too LOL.
     
  4. varian55zx macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #4
    The main problem with it is it's just too small. They need to increase the size or decrease the price of the pure SSD option to attract buyers.
     
  5. killerovsky macrumors newbie

    Joined:
    Apr 11, 2013
    #5
    What is the size of your SSD?
    --- Post Merged, Mar 22, 2018 ---
    This is just common abstract words. In reality, all depends on the size of SSD and its type of NAND flash cells. The lifetime of 24 GB SSD is much much less than of 240 GB SSD.
     
  6. GRBaset thread starter macrumors newbie

    Joined:
    Mar 19, 2018
    Location:
    The Universe
    #6
    It's the one included with the 2 TB Fusion Drive, 128 GB (actually, it's 121.3 GB, but well...).
     
  7. killerovsky macrumors newbie

    Joined:
    Apr 11, 2013
    #7
    128 GB is not bad because from some point of time Apple quietly made the entry level Fusion Drive SSDs much smaller (128GB SSD has been reduced to 24GB SSD).

    AFAIK there is no any public specs for Apple-branded SSDs, so we can only guess. But we can take a look for example on similar Samsung models (Apple often rebrand them). For example, Samsung 850 EVO 120 GB SSD has the warranty - 5 Years or 75 terabytes written (TBW) and even Samsung 850 EVO 250 GB SSD has the warranty - 5 Years or 75 terabytes written (TBW).
     
  8. ignatius345 macrumors 68000

    Joined:
    Aug 20, 2015
    #8
    Huh. My iMac 5K also has a Fusion Drive with a 128GB SSD portion. My power on hours are only 2895 and I have a "wear-leveling count" at 90%. Looks like you're just using your machine a whole lot, and rather intensively.

    Kind of a drag we don't have access to these drives like we used to in older Macs. It should be trivial to plug in a new SSD or HDD but everything is behind layers of glue now. I guess Thunderbolt is fast enough to boot off an external drive now, but that's a pretty kludgy workaround.
     
  9. GRBaset, Mar 22, 2018
    Last edited: Mar 22, 2018

    GRBaset thread starter macrumors newbie

    Joined:
    Mar 19, 2018
    Location:
    The Universe
    #9
    Yes, I know, when I went to buy the iMac, I saw that on the "How much storage do you need?" dialogue. In fact, that's the main reason why I bought the 2 TB one.

    Yep, it's a Samsung SSD (SM0128G)
    --- Post Merged, Mar 22, 2018 ---
    Or on MacBooks, which still are easily repairable. I saw the iFixit, and even though it's a difficult repair (you have to unmount almost everything!), I think I could do it. The biggest problem would be probably getting the replacement. It's an M.2 SSD, but I'm not sure if a normal one (non-Apple) would work.
     
  10. ignatius345 macrumors 68000

    Joined:
    Aug 20, 2015
    #10
    I pulled apart my old 2011 Mini to cram in an additional SSD to make a DIY Fusion Drive. I think it took like an hour or so? As long as you have good instructions, the right tools and a bit of patience, it can be kind of fun.

    But cutting into the glue and weird gaskets that are apparently inside this 5K iMac sounds a whole lot less fun. Potentially disasterous, even. I'll probably just sell it next year, a couple months before AppleCare runs out and invest the proceeds in a more current model. Which I guess is exactly what Apple wants me to do. :rolleyes:
     
  11. GRBaset thread starter macrumors newbie

    Joined:
    Mar 19, 2018
    Location:
    The Universe
    #11
    I see. I wonder if I could sell it when the Wear Levelling Count falls to zero and get a decent "discount" on a new one? Of course "I didn't know that when I sold it to you :p". That would be evil! :D;) Or I could keep it for, say, 50 years, checking it regularly, and then sell it in perfect working conditions for millions, like the Apple II is currently being sold.
     
  12. ignatius345 macrumors 68000

    Joined:
    Aug 20, 2015
    #12
    I mean, the chances are most users aren't going be riding that machine as hard as you are, but ethically? I feel like you'd want to maybe give someone a heads up.
     
  13. GRBaset thread starter macrumors newbie

    Joined:
    Mar 19, 2018
    Location:
    The Universe
    #13
    Yes, I know, it was a joke, I don't like doing unethical things. Plus, instead of selling it, I'll probably give it to a friend when it's time to upgrade it.
     

Share This Page