SanDisk Senior User
Posts: 131
Registered: ‎11-26-2015


[ Edited ]

As you know, I am a purist when it comes to SSD issues....


I have 2 companies products:  Samsung 840 and SanDisk Ultra II....  


I've had issues with both, but SanDisk Ssupport has been better than Samsung's.....


Because of the positive suppport I'm getting from SanDisk, and somewhat negative support I'm getting from Samsung... I'm making a change... and I'm informing others of it...


I hve noticed that the Samsung 840 slows down as data ages.... Starts at 200+, and slows down to 100+ after a year.. 

Samsung says 840 doesn't do this, only other models, so they haven't come out with a firmware fix for it.  (840 firmware is current).

I recently learned if I copied all data from Samsung to another drive, delete all data on Samsung, and copy it back again, the speeed of Samsung drive goes back to 200+....      !!!!!!

When the drive slows down, it drags down entire system if the program needs data from multiple drives.... and it does in this case...

This leads to a situration where the individual drive (Except Samsung) test fine, yet when used in conjunction with Samsung data,  the whole system slows down!!!




I just purchased a SanDisk Ultra II 240GB SSD to  REPLACE the Samsung 840 128GB SSD....

Tests with a single SanDisk Ultra II indicates it is faster than the Samsung 840, and Hopefully it will not degrade over time... as the Samsung SSD did.... So this should speed up slightly the Edit system throughput....


The Samsung 840 128GB SSD will be moved to a shirt pocket USB3/2 enclosure, where,  (if it slows down)  a slowdown will not be evident, and the improvement of SSD over Spinning Hard Drive for a shirt pocket enclosure will be seen.....


Once drive gets here, I'll make the change.....

SanDisk Senior User
Posts: 131
Registered: ‎11-26-2015


[ Edited ]

The drive arrived yesterday..  Made the swap from 840 to Ultra II and copied all data back onto new SSD...

Dashboard says all is current... Tests indicate it is faster than 840 was (when it was new).


Used it with Premiere Pro CS6.05 as a Cache and Video Database Drive... and it worked quite successfullly....


The reason why I relaced the 840 with an Ultra II drive is because the 840 slowed down over time, and this slowdown rippled into the Adobe applications, making all drives slower...


Samsung support says the Plain Vanilla 840 does not do this, only other versions of the 840 drive..  and my driver version is current....     


I obviously disagree with Samsung, but that doesn't get me anywhere...


So I've replaced the Samsung 128Gb 840 with a SanDisk 240GB Ultra II......


Ask me next year how it's working out!!!!   Smiley Happy!



SanDisk Senior User
Posts: 131
Registered: ‎11-26-2015


It's been a few months since I replaced the Samsung 840 with a SanDisk Ulta II drive.

If I had erased and reloaded the 840 instead of replacing with a SanDisk Ultra II.... by now the speed would have started to decrease.


(That's What Samsung Support told me I had to do:  "Your drive does not exhibit the firmware issue other models do so there will be no firmware update, but you can erase and re-load the drive if you want to speed it up")      How's that for a Non-Statement?


I am not seeing a speed decrease with the SanDisk II drives, in either a Raid 0 configuration, or single drive configuratioin.  Unfortunately I'm on on SATA II Controller..


The Samsung?  It was moved to a shirt pocket USB2/3 enclosure, whose interface is slower than the slowdown issue, but still fasteer than a spinning hard drive....     This was me making the best of  a bad situation....




SanDisk User
Posts: 44
Registered: ‎03-16-2015


[ Edited ]

The 840 uses TLC NAND just like the Ultra II does. When it comes to maximum performance, maximum durability, and the best error correction in a single package, that SSD will be either MLC-based or eMLC-based SSD. While MLC SSDs tend to give better real-world speeds, the bigger things to note is that TLC-based drives, as a general rule, have very inferior endurance and they encounter several issues with error corrections that MLC and SLC drives have much fewer issues handling. Makers are now producing tons of TLC SSDs and TLC NAND has gotten much better, but it is still very inferior to MLC IMHO. They do this because TLC costs far less than premium MLC. The full tour-de-force of SSDs IMO is one with Power Loss Protection, which is always a nice feature to have given loss of power while a SSD is writing can brick it.


Were you using TRIM with the 840? The Samsung drives seem to need TRIM more so than the SanDisk & Crucial/Micron drives that use Marvell controllers. Have you tried plugging the Samsung into a SATA port that has power but not data - and leave it for a day or so and then check to see if the SSD's CPU cleaned up the drive? (hence giving you good speeds back?) Did Samsung Magician help?


Also, have you pulled SMART data on the drive? TLC NAND has a relatively low endurance and, if you are using your SSD for intenses usage with tons of write cycles, your issue may in fact relate to the service life of the drive coming to a close.


Provided the 840 isn't sick, you should be getting better performance. I'm not sure what your model should get, but I have a Samsung 850 Pro inside my 2011 MBP-15 and an 840 Pro inside my MBP-13. Both have written several hundred gigabytes, and SMART data shows that the SSDs are still very healthy. Both had read and write speeds right around 500 MB/s, and to this day they will still attain those speeds (I ise the third party TRIM control built into OS X, I enabled TRIM when the drive was new.)

SanDisk Senior User
Posts: 131
Registered: ‎11-26-2015


[ Edited ]

Many interesting comments...

I requested what Trim settings I should do over and above the Samsung drive Utility... They (Support) said "use none", and so I followed the instructions from MFG.

Same as I've done with SanDisk.


As posted before,  in one breath Samsung Support says this unit will not need a firmware Update, because they felt that the symptoms I described, tho identical to EVO and PRO issues, were not discovered on the 840 drives.  And then, in the next breath, they provide a manual procedure for the equivalent of a Trim Cycle... "Copy all data off, erase all data, and copy it back".......


The Samsung 840 Drive is not broken, it just needs a firmware update line like the EVO and Pro Versions receiveded.  Samsung told me this will not happen.


SanDisk drive  mounted in same exact slot where the 840 drive used to reside, does not slow down over time...  Any Trim settings are whatever Windows 7-64 uses for both drives...


I encountered this slowdown procedure twice with the Samsung 840.  In both cases, since the drive was used for video cache Database, this slow-down rippled though all other drives attached to the system... So all drive throughput suffered because the lookup tables for media on other drives was delayed when the  840 slowed down.   When I copied off the database, erased all files from the 840, and then copied database back to the 840, the 840 speed increased back to when it was new.... This same 'repair' was done twice, and both times speed was returned to 'normal'.

Over time, however, this degraded....  

I have not seen this slowdown with the SanDisk Ultra II disks over time... even  in the same physical slot the 840 was in.