In the fall it was confirmed by Samsung that stale data on some 840 EVO drives would suffer performance degradation and released a tool to mitigate the issue which Al reviewed here.  The Tech Report recently heard of some cases of drives slowing even with the new EXT0CB6Q firmware installed and decided to investigate.  They took a 840 EVO 250GB SSD which had been filled with files to test the patch and was then left forgotten on a shelf for several months and tested the speeds.  The benchmarks showed an average speed between 35-54MB/s far below what you would expect to see from an SSD but in line with what users have been reported.  On the other hand another 840 EVO which has been in constant use since the firmware update shows no signs whatsoever of slowing down, though NTFS compression was recently used on the drive which could have refreshed the flash.  Obviously more testing needs to be done, keep your eyes out for updates on this new development.

"In October, Samsung patched its 840 EVO SSD to address a problem that caused slow read speeds with old data. Recent reports suggest the issue isn't completely fixed, and the results of our own testing agree."

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