Samsung prepping firmware fix for the 840 EVO’s slow read speeds with old data

Scores of people with Samsung 840 EVO SSDs have reported slow read speeds with older files. The problem seems to be most pronounced with data that’s several months old, and it may be related to voltage drift within the drive’s TLC NAND cells. Three-bit NAND is especially sensitive to voltage changes, and if those changes become too large over time, the error correction required to compensate could slow read performance considerably.

Whatever the cause, Samsung has a solution. The following statement just hit our inbox. (Emphasis mine.)

We acknowledge the recent issue associated with the Samsung 840 EVO SSDs and are qualifying a firmware update to address the issue. While this issue only affects a small subset of all 840 EVO users, we regret any inconvenience experienced by our customers. A firmware update that resolves the issue will be available on the Samsung SSD website soon. We appreciate our customer’s support and patience as we work diligently to resolve this issue.

Interestingly, the statement references the 840 EVO specifically. There’s no mention of the 840 Series, which is based on an earlier generation of Samsung’s TLC NAND. Perhaps it wasn’t affected by the same problem.

Comments closed
    • DukeA55
    • 8 years ago

    yes, this date is also posted in some german forums as well

    • DukeA55
    • 8 years ago

    Yes, as a matter of fact 840-non-EVO-series is also affected – checked it out today. It´s really quite simple – run a new Windows performance index. In my case the data transfer rate of my primary disk was the limit. After using DiskFresh the issue is solved – for a while.
    @just brew it! – normally you can flash the fw from your Windows, but- hey – speak with the devil

    • paultherope
    • 8 years ago

    My Samsung 840 EVO 500GB exhibits the problem.

    It was bought in April 2014 with firmware EXT0BB6Q (the latest firmware to date).

    • anand
    • 8 years ago

    For past updates, they’ve released bootable ISO images. They provide these for Mac users but they should boot fine on other machines.

    • just brew it!
    • 8 years ago

    News post should say “reported slow read speeds” not “reported slow writes speeds”…

    • just brew it!
    • 8 years ago

    Anyone know if there’s a way to flash the firmware from Linux, or will I need to move the drive to a Windows box to do this when they release the patch?

    • just brew it!
    • 8 years ago

    If their engineers completely understand the underlying cause they can modify the firmware to address the issue and do some regression testing to provide some assurances that they didn’t break anything else. No need to actually run the drive for months.

    OTOH, has anyone even confirmed that this is really an aging issue? It might be due to other activity on the drive, e.g. maybe their wear leveling is buggy and is causing massive page fragmentation (even of existing data).

    • HammerSandwich
    • 8 years ago

    Maybe they’re running around the problem & trusting that they didn’t flub the coding.

    Suppose they keep each block’s last-modified timestamp & add a “rewrite old cells” function to garbage collection. No old data = no slowdown.

    I’d sure like to hear about a warranty extension if that’s the case, though. Can’t imagine the impact on write amplification.

    • ronch
    • 8 years ago

    [quote<]Magic[/quote<] But, but... this ain't no Apple product! I bet it doesn't even bend!

    • Pzenarch
    • 8 years ago

    … and how do they know how many people it affects. Are they watching us? 😛

    • HisDivineOrder
    • 8 years ago

    It’s the same way they knew there wasn’t a problem until they had a fix for said problem.

    Magic.

    • ronch
    • 8 years ago

    How would they know the new firmware works? Wouldn’t they need months to test if the old-written data would be quickly read?

    • f0d
    • 8 years ago

    i think its only the people with the latest firmware that it affects

    because up until recently i was running the original release firmware (got my evo the first day i could get it) and had zero issues – it was just as fast as when i first got it

    then just before i heard about the 840evo problem (about a month ago) i decided to format my computer and thought “hey why not upgrade the firmware also” usually i wouldn’t do such things and usually go by the saying “if it aint broke don’t fix it”

    i haven’t encountered the issue yet after only a month and im hoping the fix will be out before i see any performance degradation

    • Stickmansam
    • 8 years ago

    Well the testing by the users (and myself) seem to show there is the same age/speed correlation issue that 840 EVO shows.

    It also looks more like everyone with the EVO and 840 are impacted, not just a “small subset”

    • TwoEars
    • 8 years ago

    “only affects a small subset of all 840 EVO users”

    How many? What’s the percentage? Any serial numbers? Manufacturing dates? Come on give me something here… we don’t want to flash our firmware if we don’t need to! Effing Samsung…

    • Captain Ned
    • 8 years ago

    Manage?

    • DancinJack
    • 8 years ago

    FYI since the article didn’t say, I believe the date is October 15th.

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