There have been persistent reports of performance issues with Samsung 840 SSD models for a while and Samsung has issued 2 firmware updates. We now have a decent handle on the issue all covered here:
http://www.techspot.com/article/997-samsung-ssd-read-performance-degradation/#allcomments
The main takeaways: Read performance can seriously degrade on data written as it ages. The issues are all with reading, most benchmark programs don't test performance in a way that will reveal this. The issue is hardware: some of Samsung's NAND drifts in such a way that cells become much harder to read over time. Basically Samsung has revised firmware to ensure that all data gets rewritten often enough to eliminate the problem, though it does mean the lifespans of the drives are going to be reduced. This issue could obviously be serious for reading portions of your OS which might be months or years old...
The good news is Samsung NAND are only used by Samsung and a limited number of oem products (some Dell and inside some MS Surface tablets). With the updated firmware the Samsungs should still easily exceed their 3 year warranties, just make sure you do update your firmware if you have an affected model.
The article is also instructive as to all the issues that can be involved: these Samsung's also have their performance somewhat affected by temperature...they are faster when they run hotter....go figure.
http://www.techspot.com/article/997-samsung-ssd-read-performance-degradation/#allcomments
The main takeaways: Read performance can seriously degrade on data written as it ages. The issues are all with reading, most benchmark programs don't test performance in a way that will reveal this. The issue is hardware: some of Samsung's NAND drifts in such a way that cells become much harder to read over time. Basically Samsung has revised firmware to ensure that all data gets rewritten often enough to eliminate the problem, though it does mean the lifespans of the drives are going to be reduced. This issue could obviously be serious for reading portions of your OS which might be months or years old...
The good news is Samsung NAND are only used by Samsung and a limited number of oem products (some Dell and inside some MS Surface tablets). With the updated firmware the Samsungs should still easily exceed their 3 year warranties, just make sure you do update your firmware if you have an affected model.
The article is also instructive as to all the issues that can be involved: these Samsung's also have their performance somewhat affected by temperature...they are faster when they run hotter....go figure.
