SSD problem speed

Discussion in 'iMac' started by Andrewewe, May 20, 2017.

  1. Andrewewe macrumors newbie

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  2. DeltaMac macrumors G3

    DeltaMac

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    #2
    Please post other details....
    which SSD do you have?
    Which Mac model?
    What version of macOS?
     
  3. nambuccaheadsau, May 20, 2017
    Last edited: May 20, 2017

    nambuccaheadsau macrumors 65816

    nambuccaheadsau

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    #3
    What is your problem? Blackmagic released a new version, 3.1, a day or two ago particularly for faster SSD and Flash. My iMac returned Read 681 Write 324, both of which seem high.
     
  4. Analog Kid macrumors 601

    Analog Kid

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    #4
    Some more background would certainly be helpful, but I think the problem they're referring to is the fact that after the initial write at 400MBps, it slows down below 100MBps. Making sure your version of the speed test is up to date is a good call. This can also happen if your SSD is too full and the drive needs to erase and move blocks around.

    There's just not enough to go on from this though.
     
  5. Andrewewe thread starter macrumors newbie

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  6. nambuccaheadsau macrumors 65816

    nambuccaheadsau

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  7. throAU macrumors 601

    throAU

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    #7
    I'll go out on a limb here and say that the performance issues are because its a cheaper 120 GB SSD without as many NAND chips to write to in parallel.
     
  8. Andrewewe thread starter macrumors newbie

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  9. Fishrrman macrumors G5

    Fishrrman

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    #10
    You haven't told us much, but from what I can tell it looks like you put a Sandisk 2.5" SATA SSD into an iMac?

    If so, the speeds you're seeing are normal and fairly decent for a small-capacity drive.

    As others have said, if you want more speed, a higher-end higher-capacity SSD might help a little. But you're only going to see speeds perhaps 50-75mbps faster.

    Not really worth "doing it all over again".

    What you've got isn't bad.
    Be happy!
     
  10. DeltaMac macrumors G3

    DeltaMac

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    #11
    OP's EFI partition is Fat32 (as yours would be), so that's normal.
    The main macOS (Imac) partition is, in fact, formatted HFS+, as you might expect.
     
  11. mbosse macrumors regular

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    #12
    I think this just sums it up - all perfect and as it should be!
     
  12. cynics macrumors G4

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    #13
    OP: I can't tell but did you stop the test before it completed at the end?

    Make sure you are on the latest version of Blackmagic, select the 5gb test and run it....let it complete itself.

    Your results with that drive should be around 150-200 write and 450-500 read.

    I've owned a couple of those Sandisk SSD Plus and at that capacity that was the average I saw. SSD Plus is a good drive for the cost but its not the fastest especially at 120gb capacity.
     
  13. Andrewewe thread starter macrumors newbie

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  14. cynics macrumors G4

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    #15
    Aside from the obviously language barrier I think I see the problem. Hopefully I can explain it well enough for you.

    First thing to keep in mind, Blackmagic speed test is a specific test for video production from the makers of Resolve. Its intent is to allow you to see if you storage media is capable of handling your particular work load. Its not intended as a benchmarking tool although its often used as such.

    The reason your speeds appears to be unstable is because its testing different variables. Take a look at my CrystalDiskMark from my WD Blue SSD which has similar performance to the SSD Plus however its 250gb which will inherently be faster than 120gb.

    WDBlueSSD.PNG

    Notice the speed the inconsistencies between test? That is what the level gauges are showing during the test in Blackmagic.

    When you buy an SSD the manufacturer will generally give the best results which is usually a sequential read and write (a single large file essentially). However random read and writes pulling files from all over the disk in various block sizes will be MUCH slower. Quick analogy would be if you are copying files to and from a USB. Usually you'll find 1 large file is a lot faster then many smaller files even if they equal the same amount of space. Windows actually does a great job showing this with their graph thing when copying files (I randomly pulled this from google).

    [​IMG]

    See how "unstable" that is? Its completely normal.

    I can't completely explain all the files and test nor their relevance used in Blackmagic because I'm not a professional video editor. However what I can tell you is your particular SSD appears to be functioning as well as you should expect it too. Seriously you have nothing to worry about. And in real world use its unlikely you'll notice a difference.

    If you must have a faster SSD then like recommended above you'll want a larger capacity with better technology like a 512gb Samsung 850 Evo or 850 Pro however be prepared to spend a lot more money and honestly I doubt you'll notice a difference unless you are doing very specific task constantly.

    Even though I have an SSD Plus like you I have no way of testing it without a bit of risk since its running Linux which would require me booting from a Live USB to unmount it. Even then it wouldn't be with Blackmagic. And of course Windows can't read and write to EXT4.

    If I was using your Mac I would be perfectly happy with its SSD performance given that particular drive.

    I hope this might have helped you out a little bit.
     
  15. Andrewewe thread starter macrumors newbie

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    #16
    Thank you friends for the advice !!!!!!!!!!! Will test
     

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