The chaps at TechReport noticed that the Samsung 840 EVO TLC NAND is suffering from read speed slowdowns. A few months ago this created a lot of controversy, after which Samsung was fast to release a Firmware that should have fixed this. 

Samsung issued a fix for an algorithmic error in the management routine that tracks the status of cells over time but ... that obviously does not work well enough.

If you look at the screenshot above you can see the performance degraded. This test unit 840 EVO SSD spent more than three months of the shelf, he results are pretty shocking: the months old data on the disk was only recoverable with an average read speed of 35.1MB/s. 

After formatting the disk and loading it with new data the disk averaged 430MB/s in HD Tach, there's a abvious issue with long-term degradation of data stored in the triple-bit-per-cell memory.

There sure are lots of technology oddities this week to report.

Samsung 840 EVO TLC NAND still suffering from read speed slowdowns