Over the last few weeks there has been numerous reports of a performance crippling bug found in Samsung's 840 Evo SSDs. Users over at Overclock.net found that when month old data was found on the drive, read speeds would suffer greatly.
However, fortunately for Samsung SSD users, the company has acknowledged the issue and is currently working on a fix. For those unaware of the bug, or for those it may not affect yet, there is a problem with the 840 Evo that causes the read performance of old blocks of data to drop dramatically, the reason nobody had discovered the issue until now is because it only affects LBAs that contain old data, which is classed as anything older than 30 days.
Source: @P_Combe
Anandtech got in touch with Samsung and discovered that they are aware of this bug and may have already found the source of the problem. The engineers are already working on an updated firmware, which will be distributed to end users as soon as it is ready.
There is currently no ETA for the fix so potential buyers may want to hold off on picking up the Samsung 840 EVO until this issue is officially resolved.
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KitGuru Says: It is in Samsung's best interests to get this problem patched up as fast as possible, so hopefully a fix isn't too far off. Then again, we don't know much more about the problem so its hard to say how long a fix should take. Have any of you guys been experiencing slow read speeds with an 840 EVO drive?
Source: Anandtech
It affects all EVO SSDs and also the normal 840 (slow down just takes longer to kick in). No other SSDs have been found to be affected so far.
After only 4 weeks, the data on my 1TB EVO have already slowed down to just 240MB/s on average compared to the original 510MB/s. There are already plenty of big files which read slower than 100MB/s.
Note: normal benchmark programs like AS-SSD, Crystal, Magician, Windows index don’t show the problem because they create their own new file.
“the reason nobody had discovered the issue until now is because it only
affects LBAs that contain old data, which is classed as anything older
than 30 days”
And the EVO range of SSDs has only been available for……… how long ?
Indeed … Look at my screenshot ! Do you think they would fix it quickly then ?
I got a new rig in August this year, and it has a Samsung EVO 840 128GB SSD as the operating system drive. The slowdown was easily apparent on my drive, even though it is a very young drive. I used HD Tune Pro 5.5 (Trial version) to test it before and after a secure erase and OS reinstall. What a palaver! It does speed it up, but after just 2 days of use, measured performance is starting to deteriorate again. I really wish I had gone with an MX100 instead! Slightly slower read and write speeds (450MBs) but same price. If this is “evolution”, we’ve had it! 😉