Two Samsung 840 Pro's & 1 840 have failed, 4 at [H]ardOCP (Early review sample SSD's)

Discussion in 'Memory and Storage' started by videoclone, Nov 8, 2012.

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  1. jwilliams4200

    jwilliams4200 Senior member

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    Why do you keep posting nonsense? Are you intentionally trying to make yourself look like you have no idea what you are talking about?

    The first failure was reported in the 840 Pro review when the review came out in late September.
     
  2. Hellhammer

    Hellhammer AnandTech Emeritus

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    Just spoke with Anand about this:

    The first sample, like I told you before, failed while it was being filled up with 128KB sequential data (QD=1). It would no longer power on (no current detected by a multimeter).

    The second sample died during power consumption test (that's either 128KB sequential data (QD=1) or 4KB random data (QD=32, 100% LBA space)). Our enterprise suite was run on it a couple of times before the failure occurred. It would still power on but was not being detected by the system/BIOS.

    Ironically my regular 840 is still alive after over 40TB of writes...
     
  3. jwilliams4200

    jwilliams4200 Senior member

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    Thanks for the additional information. I guess I will subject my 840 Pro to alternating bouts of 256GB of 128KiB QD1 sequential writes and 256GB of 4KiB QD32 random writes for a few days to see if it holds up or not.

    For the 40TB-written 840, have you tried any data retention tests? For example, copy a few very large files to the SSD, compute the MD5 checksums, then power off the SSD for a week. Then power it back on and check the MD5s...
     
  4. Remobz

    Remobz Platinum Member

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    I am crossing my fingers that all goes well.
     
  5. Hellhammer

    Hellhammer AnandTech Emeritus

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    No, I haven't done that (at least yet). The WLC (Wear Leveling Count) is only at 75 so I need to hammer it a bit more as currently the data retention should be much longer than a week (most manufacturers rate their MLC NAND so that the data retention time is 1 year after the P/E cycle count has been achieved). The data I have so far suggests that the WLC will hit 1 after ~1300 P/E cycles.
     
  6. taltamir

    taltamir Lifer

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    1. Its supposed to retain power for 10 years. Testing a week is not useful.
    2. MD5 checksum failure requires that sufficient cells would fail to the point where built in ECC cannot correct it (recall that all modern SSDs have ECC to compensate for their increased error rate). So even if some data was lost, it will not show in MD5 checksum unless a whole bunch of data was lost
     
  7. jwilliams4200

    jwilliams4200 Senior member

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    Wrong. The data retention decreases as erase cycles increase. According to one common specification, the data retention should still be at least 1 year at the rated maximum erase cycles for the device. But if you surpass the rated erase cycles, the data retention time can become very short, potentially less than a week, or even less than a day.

    In addition, the Samsung 840 uses TLC flash and I am not sure if Samsung adheres to that specification. Furthermore, Samsung has not specified the erase cycles lifetime of the flash in the 840, as far as I am aware.
     
  8. jwilliams4200

    jwilliams4200 Senior member

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    This is the 250GB model that you are testing, right?

    40TB / 256 GiB = 145.5

    So the erase cycles should be at least 145.5, but probably higher since average write amplification should be greater than 1.0

    I think some of the early Samsung 830s had a firmware bug where the WLC did not get updated reliably. I wonder if something similar is happening with your 840.
     
  9. Hellhammer

    Hellhammer AnandTech Emeritus

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    1,000 P/E cycles is what I heard/saw while I was in Korea. While the info was straight from Samsung, it isn't exactly official (I saw the figure during a fab tour).

    Yup.

    I should note that the WLC was at 89 when I started endurance testing. I had run all our regular tests on the drive and used it as a secondary boot drive for a few weeks before I started testing, hence it wasn't 100.

    So far the WLC has been going down linearly and the results make sense. The reported Total LBAs Written are way off though (I've tried SSD Magician, GSmartControl, Intel SSD Toolbox and CrystalDiskInfo - all report different numbers and they just don't make any sense). Fortunately I can still get the host writes from the average write speed reported by Iometer; WA should also be close to 1.0 as I'm using incompressible 128KB sequential data (QD1).

    It's of course possible that the reporting is off and to be honest I wouldn't be surprised if it was (you will find out why in a few weeks when we are allowed to talk about this one thingy).
     
  10. jwilliams4200

    jwilliams4200 Senior member

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    Ah, you mean the normalized value (of attribute 177). Right?

    I thought you were giving the raw value of attribute 177, which (at least on the 840 Pro) appears to indicate the average number of erase cycles for the flash.
     
  11. Hellhammer

    Hellhammer AnandTech Emeritus

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    Yeah, I've been recording the normalized value. Didn't know that the raw value might indicate the number of erase cycles, I'll start recording it now to see what it gives us. It's at 250 now, which would mean 1,000 P/E cycles since the normalized value is 75.
     
  12. taltamir

    taltamir Lifer

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    1. Do you have any idea how long it takes to exceed the PE limit on a drive even when that is what you are intentionally attempting to do?
    2. You started with a "Wrong." mr genious, but how does the "facts" you provide actually contradict my arguments?
    3. I love how you conveniently ignore the parts of the argument you don't have a "refutation" (and I use that word generously) for.
     
  13. jwilliams4200

    jwilliams4200 Senior member

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    Yes, of course. I've done it.
     
  14. jwilliams4200

    jwilliams4200 Senior member

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    Good, it looks like what you heard in Korea agrees with what attribute 177 is indicating -- 1000 erase cycles for the new TLC flash in the 840. So, for the 250GB SSD, it should take around 250 to 275TB of sequential writes to hit the erase cycle limit.
     
  15. taltamir

    taltamir Lifer

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    1. On what drive, specifically
    2. How long did it take, specifically
     
  16. jwilliams4200

    jwilliams4200 Senior member

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    You should not need to ask me...this is hardly rocket science. But for the sake of the mathematically and logically challenged:

    (secs to exhaust erase cycles) = (flash capacity of SSD in MB) x (rated erase cycles) / (best sustained sequential write speed in MB/sec)
     
  17. taltamir

    taltamir Lifer

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    1. You have been rude throughout, stop with the put downs. Personal attacks are not allowed.

    2. I didn't ask you for the equation, I know how to do math. I asked you how long it took YOU to do it.

    You claim to have exceeded the PE endurance limit on a drive, not to have done the math. I want to know the exact make, model, and size of the drive you have exceeded the limit on, and I want to know how long it took in actuality (not in theory).

    Also, the equation you gave? It cannot be solved without plugging in information which you are REFUSING to give. Such as the make and model of the drive in question.
     
  18. jwilliams4200

    jwilliams4200 Senior member

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    The SSDs I have worn out are not relevant to this thread. I'm not sure why you are so obsessed with me and my equipment.

    Is it really so difficult for you to look up the sequential write speed of an SSD you are interested in, and then do some simple arithmetic using the formula I already provided to you? I know you can count at least to 3. I thought that anyone posting in this thread should be capable of basic arithmetic.
     
  19. katkah

    katkah Junior Member

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    I read the review just before I purchased on 11/06/12 and there was no fail written in that report! :colbert::p I know how to install benching software and hit start too! :whiste: Read too! :rolleyes: Show me a google cache of the report that says failure prior to the date of this posting! YOU CAN'T because it doesn't exist.;):cool:
     
  20. Hellhammer

    Hellhammer AnandTech Emeritus

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    There has been a mention of the failed unit since the review was published. Now the review has been updated with a mention of a second failed unit.
     
  21. jwilliams4200

    jwilliams4200 Senior member

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    Not only did your reading comprehension fail on that article, you do not understand how google cache works. It only caches one copy of a page, the most recent one that it has successfully indexed. Since the review was updated when the second drive failed (and google indexed it), that is the one in google's cache.

    The Internet wayback machine does not have any version of the article stored.

    However, all you have to do is look at the article's comments, several of which mention the failure. For example:

    http://www.anandtech.com/show/6328/samsung-ssd-840-pro-256gb-review?all=true

     
  22. Engineer

    Engineer Elite Member

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    If you're talking about Anand's review of the 840 Pro, he did indeed have that the first drive failed and a replacement was either on the way (or already received...don't remember which). It was in the review when it was published because I remember reading it and thinking it might be good to hold off on this before making a decision.
     
  23. zero koopa

    zero koopa Member

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    well I am glad I just saw this article after I ordered from new egg
     
  24. iaco

    iaco Junior Member

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    DIPM being disabled could be a factor though it wouldn't explain why the non-pro is fine.
     
    #74 iaco, Nov 12, 2012
    Last edited: Nov 12, 2012
  25. jwilliams4200

    jwilliams4200 Senior member

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    I don't follow. DIPM being disabled where, exactly?

    And nice de-lurk! ;)
     
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