If you have a Samsung 840 EVO SSD, you may have noticed a loss in performance if you've owned it for a long while. Unfortunately, a bug in the design of the 840 EVO causes older blocks of data to deteriorate, resulting in poor read speeds when accessing older data. Fortunately, Samsung acknowledged this bug and released a fix.
The new firmware's version number is EXT0CB6Q, and it can be downloaded from Samsung immediately. What this firmware does is rewrite older data blocks, ensuring that the data remains fresh, avoiding excessive read-retry processes.
The update can be installed through Samsung's Magician software, or you can run it off of a bootable disk. Either way, be sure to back up your data in case something goes wrong.
You can download the EXT0CB6Q firmware directly from Samsung here. If you're unsure about how to install the new firmware, you can read through Samsung's installation guide here.
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(I need to update this since it is so high on the comments list. I was wrong. I admit it. I misinterpreted the description of how the patch worked. The firmware isn't continually rewriting the data. The firmware does actually fix the performance issue for future written data, but then the utility rewrites the existing data so it isn't stuck with the poor performance. If you just run the firmware update, the old data may still have the performance issue. So, use the utility. It fixes everything up nicely.)
The majority of fixes turn out to be just that- workarounds. Probably the only real fix they could do would be a HW change that would affect only new models. I'd rather deal with a workaround "fix" than having to buy a new SSD to get my performance back...
ah, that's good to know. Thanks for that. I haven't been home to check it out yet.