Subject: Editorial, Storage
Manufacturer: PC Perspecitve
Tagged: tlc, Samsung, bug, 840 evo, 840

Investigating the issue

** Edit ** (24 Sep)

We have updated this story with temperature effects on the read speed of old data. Additional info on page 3.

** End edit **

** Edit 2 ** (26 Sep)

New quote from Samsung:

"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."

** End edit 2 **

Over the past week or two, there have been growing rumblings from owners of Samsung 840 and 840 EVO SSDs. A few reports scattered across internet forums gradually snowballed into lengthy threads as more and more people took a longer look at their own TLC-based Samsung SSD's performance. I've spent the past week following these threads, and the past few days evaluating this issue on the 840 and 840 EVO samples we have here at PC Perspective. This post is meant to inform you of our current 'best guess' as to just what is happening with these drives, and just what you should do about it.

The issue at hand is an apparent slow down in the reading of 'stale' data on TLC-based Samsung SSDs. Allow me to demonstrate:

840 EVO 512 test hdtach-2-.png

You might have seen what looks like similar issues before, but after much research and testing, I can say with some confidence that this is a completely different and unique issue. The old X25-M bug was the result of random writes to the drive over time, but the above result is from a drive that only ever saw a single large file write to a clean drive. The above drive was the very same 500GB 840 EVO sample used in our prior review. It did just fine in that review, and at afterwards I needed a quick temporary place to put a HDD image file and just happened to grab that EVO. The file was written to the drive in December of 2013, and if it wasn't already apparent from the above HDTach pass, it was 442GB in size. This brings on some questions:

  • If random writes (i.e. flash fragmentation) are not causing the slow down, then what is?
  • How long does it take for this slow down to manifest after a file is written?

Read on for the full scoop!

SandForce finally patches elusive 2200 series SSD controller bug. OCZ issues firmware, others soon to follow.

Subject: Storage | October 17, 2011 - 09:25 PM |
Tagged: ssd, sandforce, ocz, firmware, bug, BSOD

Over the past few months, we had noted a seemingly disproportionate surge of negative reports from users of SandForce-2200 based SSD's. These include OCZ's Vertex and Agility 3, Corsair's Force 3 and GT, Patriot's Pyro and Wildfire, along with many others. The complete list is available in our handy SSD Decoder.

The issue at hand was random BSOD's, with the possibility of an eventual complete failure of the SSD, rendering it unrecognizeable to the BIOS or Operating System. More details (and the fix) after the break:

110529-213748-6.5.jpg

I witnessed this personally, as the SF-2281 pictured above suffered the same fate when we attempted to use it a few weeks ago.

Today (hopefully) marks the answer to everyone's prayers. SandForce issued base firmware 3.3.2 for SF-2000 series controllers.

snap-397-.png

OCZ's Toolbox software V 2.40.02 can patch OCZ's line of SF-2200 SSD's with the new fix.

The release notes follow (and seem to lack mention of the aforementioned bugfix):

OCZ Toolbox version 2.40.02
---------------------------
- Modified Identity data display
- Fixed Smart data display for power fail backup attributes
- Added BIOS update for Hybrid drive

Known Issues:
- Update Firmware feature prohibited for primary drives with 1500 & 2000 controllers
- Intel RST Driver 10.1.0.1008 prohibits SSD detection

OCZ's press tidbit for the new firmware(s):

OCZ is pleased to announce that the cause of a BSOD issue experienced by some SF-2000-based drive owners has been identified by OCZ and SandForce. A new firmware update which directly addresses this BSOD occurrence related to SF-2000 based SSDs is available here. All newly manufactured OCZ SF-2000 based SSDs will feature the new 2.15 firmware revision (which is based on SandForce firmware version 3.3.2.) We highly recommend that any customers that have experienced the BSOD issue update their firmware to 2.15.
 
We sincerely appreciate the support from our customers, and if any customers have any questions or require additional support please do not hesitate to contact a customer service representative and we will be happy to address any questions or concerns.

If you own any of the affected SSD's, I highly recommend updating as soon as possible. Until then, I also recommend you back up any data present on these drives, as the above statements confirm the presence of an issue that can potentially brick your SandForce SSD at any moment.

Remember, patch only applies to the 2200 Series controller (i.e. SandForce SSD's capable of SATA 6Gb/sec).