We've been covering the issues surrounding Samsung's SSD 840/840 Pro lately. The issue was first discovered when Anand's pre-production review sample died during testing and we also noted that in our initial review. Samsung quickly sent us another drive but it also failed after a couple of days of testing. My SSD 840 managed over a month but ironically enough, it died right after I had completed endurance testing.

Earlier Samsung told us that all review samples including our three shipped with a pre-production firmware that had a bug in it causing the failures (retail units were shipped with a newer firmware without the bug). At the time we didn't know what exactly was wrong in the firmware, but now we do. When the drive was issued a secure erase command, it would clear all table mapping information at the Address Translation Layer (ATL) but not at the Host Interface Layer (HIL). The data in both layers needs to be up-to-date for the drive operate properly, so when a write request came in, the controller wasn't able to map the data correctly, which caused the firmware to hang. An SSD obviously can't operate without a functioning firmware so from a user's standpoint, it looked like the drive had completely died even though only its firmware was broken.

All our three failures support this explanation. Our first 840 Pro sample died during a 128KB sequential write pass that we use to pre-condition our drives for enterprise tests, but the drive was secure erased just before beginning to fill the drive. The second 840 Pro died during power consumption testing but again it was secure erased right before starting the test. The regular 840 actually died when I tried to secure erase it. The secure erase command resulted in an error so I power cycled the drive but it was no longer detected by the system after reconnecting it. 

Comparison of Samsung SSD Firmware Versions
  Pre-Production Retail
Samsung SSD 840 Pro DXM02B0Q DXM03B0Q
Samsung SSD 840 DXT05B0Q DXT06B0Q

The good news is that all retail units have shipped with a newer firmware, only reviewers and others who have access to pre-production units were affected by this bug. 

For users considering the SSD 840/840 Pro, this should be reassuring news. The 840 Pro is still the fastest SATA 6Gbps SSD we have tested and it's definitely one of the top choices where performance is concerned today. The TLC NAND based SSD 840 is more mainstream focused but from what I have seen, it seems to be fairly competitively priced. The SSD 830 spoiled many with low prices but that was only to clear stocks. If you can still find a bargain SSD 830, don't hesitate to pull the trigger as those won't be available much longer, but we're more comfortable recommending the 840/840 Pro now.

While long-term reliability is still unknown, if history is any indication the 840/840 Pro are in good company as the 830 was a solid drive. Our third 840 Pro with the new fixed firmware has been going strong for weeks now and we have even recreated the scenarios that killed the earlier samples. We are also waiting for more samples from Samsung to test all capacities of SSD 840 and 840 Pro, so stay tuned!

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  • Entropy512 - Wednesday, January 30, 2013 - link

    How did this even make it into a preproduction firmware for a device in late 2012?

    This is the exact same issue that a large variety of Samsung eMMC flash chips made in 2011. They fixed the issue in late 2011.

    At the very least: VYL00M, KYL00M, MAG4FA fwrev 0x19 all had this EXACT same bug. VYL00M fwrev 0x25 (present in the Galaxy Nexus) did not. They were aware of this early enough that the mainline Linux kernel was patched to avoid this issue in early September:

    http://git.kernel.org/?p=linux/kernel/git/torvalds...

    I can tell you that Samsung was fully aware that secure erase was an issue in many of their flash chip firmwares in June 2012 - so how was it that even preproduction firmware had not been properly tested with secure erase in late September 2012, nearly a year after they had fixed the same firmware bug in their eMMC chips.

    I would not be surprised if one of Samsung's SSDs released late in 2013 starts dying after a few months of usage just like VTU00M fwrev 0xF1 (found in many GT-I9300 phones) did, considering how mobile device eMMC bugs seem to show up in their desktop products after about a year.
    Reply
  • midijamm - Saturday, June 01, 2013 - link

    I have been trying to update the firmware in my 840 in my macbook pro. It seems to be a bit complicated. It works fine as it is except you cam't close the lid as it will not wake up. (I have seen this before with a kingston) Also in reading this and other forums I have repeatedly seem testimonies that it is a fast drive, but that is not so in my Mac. It boots in 30 seconds which is twice as fast as a spinner but OWC and Crucial drives boot in 10. Is this a firmware issue or is the 840 really that much slower? Anyone know? Reply
  • hakkiro - Friday, June 28, 2013 - link

    Hello !

    I had one of my two 840 Pros die (?) this week.

    Here's the story, and a plea for help (see the end of message) from someone knowledgeable :

    I bought two 840 Pro (256Gb) in mid February 2013.
    Both came with DXM03B0Q firmware.
    As I purchased after reading through all relevant 840 Pro AnandTech articles I was aware of the firmware issues and the first thing I've done was upgrading (from bootable ISO created with Samsung Magician) to version DXM04B0Q.

    One of the drives was setup as system drive with Win 8 Pro.
    That drive has been going since and hasn't thrown any problems at all.

    The other drive was setup as storage for my video work.

    Both were formatted NTFS (with default cluster sizes) and connected to native Intel SATA III ports on my Asus P8P67 Mobo.

    As I said the system drive is going strong (fingers crossed) so the rest of the story concerns the other (storage) drive.

    All was well for a while.
    After a couple of months the drive started "disappearing" from SATA bus.
    This behaviour was random and I could never recreate it at will (technician's nightmare).
    A reboot or a Cold Boot would always bring it back, though.
    In the process, I eliminated SATA cables and ports by replacing cables and running the drive from a different port.

    The other day the drive has gone for good.
    It appears dead.
    Well, almost - read on.

    Almost all symptoms I'm having are same or similar to other tales of 840 Pro woes I, since, read.

    Drive does not show inside BIOS nor on the POST screen readouts.
    When connected to SATA bus it is preventing my machine from booting to desktop.
    The machine's HDD access LED stays firmly lit during boot-up process and the screen never gets to desktop.
    If I physically disconnect the drive during the boot-up the said HDD access LED resumes the usual random flashes indicating reading from System Drive and System loading and, seconds later the boot completes and I get to the desktop.

    If I now connect the faulty drive again - (My MoBo supports HotPlugging) the HDD access LED lights up solid but no drive appears in Windows explorer or Windows Disk Management console.

    The drive appears in Device manager, however, but under a generic name, ie : "SAMSUNG SATA SSD" (caps intentional) as opposed to "Samsung SSD 840 PRO Series" (which is how my System drive appears next to it under Device Manager). My "Safely Remove Hardware" green icon also appears in the System tray and lists the drive (under "SAMSUNG SATA SSD").
    If I attempt to click on it - nothing happens (ie : no usual message "Safe to Remove", etc ...).
    All the while, from the moment of hot-plugging the drive the HDD access LED stays firmly lit.

    Neither Windows Explorer nor Disk Management Console nor Samsung Magician utility see the drive.

    If I leave the drive connected and proceed to shut down the machine I get the same behaviour as the one described during the start-up, ie :
    HDD access LED stays lit while the machine remains in "Shutting Down" screen yet never actually shuts down until I physically pull the drive out from the HotPlug bay. At this point HDD access LED resumes the familiar flashing pattern indicating read/write processes on System Drive and the machine eventually shuts down after a few seconds.

    I eliminated further variables by connecting it as an external drive using a SATA->USB3 enclosure.
    No play :(

    As I have some data on this drive I'd hate to loose (surprise, surprise ...) - here's my $1000000 question :

    Since the drive entry appears in Device Manager after hot-plugging the drive - is there any Windows-based (not DOS) software that will allow me to access the drive to perform either a firmware re-flash (a new DXM05B0Q firmware is now available) or data recovery ?

    To recap : the drive does not appear in BIOS nor Windows Explorer nor Windows Disk Management Console nor is it seen by Samsung Magician nor any other Windows (or DOS - I tried SpinRite) utilities I know of.

    Please advise.

    PS
    (I have obtained an RMA from the original retailer - Ebuyer, here in UK but I'd like to exploit all possible data recovery options before I send it off).
    Reply
  • FullForce - Tuesday, July 16, 2013 - link

    I purchased my Samsung 840 Pro 256gb in March of 2013. I have been experiencing the same problems as yourself and today it finally seems to of died. I can't figure out how to try updating firmware like yourself and it seems impossible. Parted Magic can't see the drive as well. Exactly the same symptoms as yourself though.. Reply
  • hokeren - Sunday, August 25, 2013 - link

    Looks like I am in the same boat as you guys, now with a broken 840 Pro 256GB drive!
    Mine just died today.
    It does not show up in BIOS any longer, and when trying to find i hooked up to a USB cradle, it shows a 100MB uninitialized.
    If I try to initialize it as MBR, WIndows reports an I/O error has occured.
    No luck so far getting any data from the drive :(
    Reply
  • benson95 - Saturday, December 21, 2013 - link

    Can anyone help? My 840PRO failed a few days ago. A check also shows only 0.93GB, SN: nil and Firmware: IE'. And when you go to do the performance test on magician, it says "no volumes found on selected drive". Windows fails to boot. I get "media failure, check plug" message. I lost all my past 8 months worth of travel pics. Is there anyone who can help? What are the chances of recovering my data? Reply

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