Firmware Update to Fix the Samsung SSD 840 EVO Read Performance Bug Coming on October 15th

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• ThisWasATriumph - Friday, September 26, 2014 - link

  In the meantime, DiskFresh can read and write each sector once, which will temporarily fix performance issues. I used it on the first 40% of my drive and its back to full speed. http://download.cnet.com/DiskFresh/3000-18512_4-75...

• Maltz - Friday, September 26, 2014 - link

  I've wondered about booting my MacBook Pro into single-user mode and doing a dd if=/dev/rdisk0 of=/dev/rdisk0 bs=1m. Seems like that should work, but it would put a lot of wear on the drive. If it's only about three weeks away, I think I might just wait for the firmware update.

• dylan522p - Friday, September 26, 2014 - link

  The firmware update is pretty much just gonna be aggressively moving data around so that it never gets old and the voltages in the cells do not drop.

• boozed - Friday, September 26, 2014 - link

  How sure of this are you?

• Maltz - Friday, September 26, 2014 - link

  There was one school of thought that speculated that the problem was fading charges in the TLC NAND, but given the complete lack of data loss, I personally find that unlikely.
  
  Another theory was that the wear-leveling routines were moving data around in such a way that eliminated the parallelism between NAND modules, thus slowing down the drive. If this is the case, the re-arranging of data to speed things back up would be a one-time event, but would still have to occur.
  
  But, it's all just speculation at this point, of course.

• hojnikb - Saturday, September 27, 2014 - link

  Well, thats a pretty bad theory. Even if data was moved around in such manner, it would still be faster than 50MB/s (or even less in some cases). ToggleDDR is good for ~400MB/s, so even if data is on a single package for some reason, it still woulnd hit performance so hard.

• Solid State Brain - Friday, September 26, 2014 - link

  Putting aside controller strategies (read: ECC) that on normally functioning drives are probably occurring to ensure that read operations remain reliable with wear and usage, if static data has the chance to become old with normal usage patterns it likely means that the controller wasn't moving it around at all. Every time the SSD's wear leveling count increases by one, all NAND flash cells are supposed to have been written on once on average and this is going to happen at least once a month with just 4-5 GB of daily host writes on a 250GB drive on average, assuming a write amplification of 2, which would represent a very light usage.
  
  So it's not a matter of "aggressively moving data around", but to actually get it to move around in the first place, assuming the bug isn't affecting something else instead (like for example the metadata associated with the recorded data as it gets shuffled around).

• chrysrobyn - Monday, September 29, 2014 - link

  How about dd if=/dev/rdisk0 of=/dev/null bs=1m? DD will read all the sectors, but it won't put them anywhere, so no write wearing.

• Mugur - Saturday, September 27, 2014 - link

  Hopefully they will release a fix for the old 840 too... I have 4 of these at work and I was just going to make a big storage spaces pool with 2 layers out of them. Not sure that the bug will show in this context, but if there will be some static most accesed files moved to ssd by storage spaces I assume yes.

• Death666Angel - Saturday, September 27, 2014 - link

  I have a 840 500GB as my system and steam drive here. Haven't noticed any slow downs at any point during the last 18 months I had it. Benchmarks during that time always showed it operating a few 10s of MB below peak performance for my SATA II (old P55 chipset) and now SATA II (Z87) connections.