Introduction
Samsung’s fix for the EVO tested!
** Edit **
The tool is now available for download from Samsung here. Another note is that they intend to release an ISO / DOS version of the tool at the end of the month (for Lunix and Mac users). We assume this would be a file system agnostic version of the tool, which would either update all flash or wipe the drive. We suspect it would be the former.
** End edit **
As some of you may have been tracking, there was an issue with Samsung 840 EVO SSDs where ‘stale’ data (data which had not been touched for some period of time after writing it) saw slower read speeds as time since written extended beyond a period of weeks or months. The rough effect was that the read speed of old data would begin to slow roughly one month after written, and after a few more months would eventually reach a speed of ~50-100 MB/sec, varying slightly with room temperature. Speeds would plateau at this low figure, and more importantly, even at this slow speed, no users reported lost data while this effect was taking place.
An example of file read speeds slowing relative to file age.
Since we first published on this, we have been coordinating with Samsung to learn the root causes of this issue, how they will be fixed, and we have most recently been testing a pre-release version of the fix for this issue. First let's look at the newest statement from Samsung:
Because of an error in the flash management software algorithm in the 840 EVO, a drop in performance occurs on data stored for a long period of time AND has been written only once. SSDs usually calibrate changes in the statuses of cells over time via the flash management software algorithm. Due to the error in the software algorithm, the 840 EVO performed read-retry processes aggressively, resulting in a drop in overall read performance. This only occurs if the data was kept in its initial cell without changing, and there are no symptoms of reduced read performance if the data was subsequently migrated from those cells or overwritten. In other words, as the SSD is used more and more over time, the performance decrease disappears naturally. For those who want to solve the issue quickly, this software restores the read performance by rewriting the old data. The time taken to complete the procedure depends on the amount of data stored.
This partially confirms my initial theory in that the slow down was related to cell voltage drift over time. Here's what that looks like:
As you can see above, cell voltages will shift to the left over time. The above example is for MLC. TLC in the EVO will have not 4 but 8 divisions, meaning even smaller voltage shifts might cause the apparent flipping of bits when a read is attempted. An important point here is that all flash does this – the key is to correct for it, and that correction is what was not happening with the EVO. The correction is quite simple really. If the controller sees errors during reading, it follows a procedure that in part adapts to and adjusts for cell drift by adjusting the voltage thresholds for how the bits are interpreted. With the thresholds adapted properly, the SSD can then read at full speed and without the need for error correction. This process was broken in the EVO, and that adaptation was not taking place, forcing the controller to perform error correction on *all* data once those voltages had drifted near their default thresholds. This slowed the read speed tremendously. Below is a worst case example:
We are happy to say that there is a fix, and while it won't be public until some time tomorrow now, we have been green lighted by Samsung to publish our findings.
thanks for the update
thanks for the update
Allyn, So is it safe to buy a
Allyn, So is it safe to buy a Samsung 840 Evo again? Or would you recommend another brand/model instead?
Would like to know the same
Would like to know the same thing.
I like Samsung EVO SSD’s but was on the fence to hold off.
Should I go Crucial which I’ve never owned or buy Samsung again?
Nah..Samsung has said they
Nah..Samsung has said they have been able to replicate the issue and are actively working on a fix. you’ll be fine going with the Samsung drives + its not a defect in the drive itself..its just an issue in how the software and error correction handles the data after a while they need to fix.
+ its not an issue on all models of Samsung SSd’s either.
Just grab mx100 and call it a
Just grab mx100 and call it a day. Its a better option overall ever since it came out.
Its faster, cheaper, MLC flash !!!, partial powerloss protection.
I really dont get why people still buy EVOs. You’re pretty much just paying more money for a inferior drive, just because it has a fancy samsung sticker on it and was once a good buy.
I’ve always recommended these
I've always recommended these for their balance of price and performance. I paused that recommendation until we knew there was an update coming, but now that it's out and appears functional, I'll recommend them and revisit after we've had data sitting on these drives for a few weeks.
Thanks for keep on this
Thanks for keep on this Allyn. I’ll keep holding off for a verdict.
Grab mx100 🙂
Why pay more
Grab mx100 🙂
Why pay more for less ?
It has even worst write
It has even worst write endurance than the 840 evo
MX100 performance is not
MX100 performance is not great at smaller capacities. An 840 EVO 120GB walks all over an MX100 128GB, especially in write speeds.
The EVO’s are a worst value
The EVO’s are a worst value compared to higher end SSD’s such as the pro series when you consider the price you are paying, and how many TB of data the drive can handle in writes before it begins to fail.
The EVO’s pretty much begin to rapidly burn through the over provisioned cells after about 100TB Due to the uncertainty of how an SSD will handle a failure state, in terms of reliability, the SSD is pretty much gone at this point, MLC drives can often handle 5 to 10 times that amount.
Also keep in mind that even though SSD’s have spare sectors, they are still used during wear leveling, this means that when a few cells start to fail, you can bet that all of the cells are pretty close to their limits which is why you see on the tech report article, the SSD’s will handle many TB with no problem but at one point you suddenly start to get a ton of reallocated sectors before the SSD randomly dies.
If you regularly do video editing using programs like adobe premiere pro, expect to put 40+ TB of writes to your SSD each year, even if your source videos are on another drive due to how these programs cache working data. (And moving the cache to a different drive is not an option as it defeats the purpose of using an SSD).
Not sure if you are aware,
Not sure if you are aware, but 840's (not Pro) have been tested to nearly a petabyte in actual use, so given your usage figure, one would last well over a decade.
Thats Great News and thanks
Thats Great News and thanks for the update 🙂
I just built a new system with a 1Tb 840 Evo for games and and some light file storage and after i heard the news of performance loss on the Podcast i got nervous. This is good news.
One another Note i must thank-you again for the suggestion on the podcast about the Drivefresh software. I have used it on 3 systems i own and the 3 drives that i use to store data long term locally. (i have 2 other offsite storage solutions as well). Just a word of warning to those getting it ..the free home user version works very well to “refresh” your data on the HDD but it takes many hours to complete…my 1 system with a 1.5 Tb drive full of movies and pictures took over 20 hours to complete.
Do you know if it is possible
Do you know if it is possible to run the tool on a 840 EVO using bitlocker under windows 7 x64?
I already run diskrefresh once and everything went fine, but maybe Samsung is using a different approach that could have issues with a bitlocker-encrypted drive.
The tool doesn’t support RAID
The tool doesn't support RAID or dynamic disks, so bit locker is probably unlikely. Anyone running in non-standard configurations should seriously consider emptying the EVO and applying the update in a simple partition / format state.
I ran it on a Bitlocker
I ran it on a Bitlocker encrypted drive and it worked fine.
Glad to hear Samsung has got
Glad to hear Samsung has got a fix and that it works!
I’m curious how the firmware update works. Is this something that the tool does automatically? In the past, on my ASUS M5A99FX PRO R2.0 I had to create a USB boot drive to flash the firmware to the drive. I thought this was because the Samsung Magician tool didn’t work with AMD chipsets. Is this no longer an issue?
Per their documentation, it
Per their documentation, it should work under AMD, but only with their newest driver, or by reverting back to the MS AHCI driver.
I am using RAID0 is RAID
I am using RAID0 is RAID supported?
I’m in your boat, raid 0 two
I’m in your boat, raid 0 two 250 evos. I don’t feel like doing a clean install.
FYI, raid people, image your
FYI, raid people, image your array, then update each ssds and then setup raid again and restore image…
if you dont have a external hdd for data, get one…
Macrium Reflect can do this
http://www.macrium.com/reflectfree.aspx
I added the sequence you’d
I added the sequence you'd have to follow to the middle of page 2.
does not work on drives
does not work on drives connected to raid, must be ahci, at least according to techreport.com
No go on RAID or dynamic
No go on RAID or dynamic disks.
Thank you Allyn!
Thank you Allyn!
You guys need a Like button.
You guys need a Like button. It’s articles like this that keep us coming back to PCper
Please, no. This isn’t
Please, no. This isn’t Facebook and it doesn’t need to be.
Amen!
Amen!
(but it’s too easy to
(but it’s too easy to double-submit comments)
Apologies. We are working on
Apologies. We are working on crushing that bug, but it may get rolled into a complete site update.
So when are we going to be
So when are we going to be able to get our hands on the restoration tool? Can any of the pcper guys post a download link?
“We are happy to say that
“We are happy to say that there is a fix, and while it won’t be public until some time tomorrow, we have been green lighted by Samsung to publish our findings.”
Does this include 840 Pro
Does this include 840 Pro models or is it specifically 840 EVO?
Pro is not affected, but many
Pro is not affected, but many have seen this same slow down on the original 840 (which is also TLC).
agreed, i have a pair of 840
agreed, i have a pair of 840 pros and they are NOT affected, but allyn do you know if 840 EVO mSATA is affected or not?
and yes i also have a 840
and yes i also have a 840 120GB (the old non-evo/non-pro series) and its affected
MSATA EVOs are effected, and
MSATA EVOs are effected, and will update with the same tool. We just confirmed this here.
Thanks for the update Allyn.
Thanks for the update Allyn. Samsung has only mentioned the 840 EVO, does this not apply to the vanilla 840 too? They’re both TLC SSDs. My system has a 500GB Samsung 840 in it, though I seem to be lucky enough to have not had this issue.
Some with the standard 840
Some with the standard 840 have reported the issue, but Samsung has not confirmed that, so the best I can say is keep an eye on it in the future.
“Out of five drives we tested
“Out of five drives we tested the process on, one of them corrupted its MFT during the post-reboot process, and a subsequent reboot resulted in the loss of nearly all data.”
Uh… that’s kind of a BIG deal.
I agree, but this is probably
I agree, but this is probably the most technically difficult update process I've seen for any device. The fact that Samsung was able to put this functionality into a tool that can rearrange data at the flash block level behind the OS's back, even while that OS is installed on the very drive being manipulated, is no small feat. The drive that errored was nearly filled to capacity with steam downloads (which heavily fragments the flash given the way Steam writes downloaded game data). I had emptied just enough of it to get the update to run. If users are more conservative with their preparations for this update, they should be fine, especially if they have backed up prior to running it.
Also note, the drive was not bricked, it just need to be reformatted (to be conservative) because of the corruption. I chose to repartition it, as that forces the whole drive to be TRIMmed.
Yes, it’s no small feat. Can
Yes, it’s no small feat. Can you comment on whether the tool works on a non-system drive basis, i.e. can one use another system to fix these drives?
That should be safer, and ideally it would be possible to fix multiple drives simultaneously.
Yes it works on EVOs
Yes it works on EVOs connected as a secondary drive (that's what we did for testing), but you must complete the full sequence (including the shutdown/power cycle) on each drive before moving onto the next.
If the tool “can rearrange
If the tool “can rearrange data at the flash block level behind the OS’s back, even while that OS is installed on the very drive being manipulated” then why does it need NTFS on it in order to run?
If the tool “can rearrange
If the tool “can rearrange data at the flash block level behind the OS’s back, even while that OS is installed on the very drive being manipulated” then why does it need NTFS on it in order to run?
makes sense to backup? i
makes sense to backup? i learn that the hard way updating firmware on a hard drive years ago
soo remember kids, backup before firmware upgrading
Big question, Does this help
Big question, Does this help the same problems with the non evo 840? same problem, so same update or not?
We’re still working on an
We're still working on an answer to that one.
did this issue exist on the
did this issue exist on the msata 840 evo
Yes, and the same update will
Yes, and the same update will correct the issue as well. MSATA is only a packaging difference. The drive itself functions identically.
thx for the heads up
thx for the heads up
Well i got 750GB 840 EVO in
Well i got 750GB 840 EVO in my iMac, in my Macbook and a 250GB in my PS3.
What about those users? How will/can they update their drives, any informations on this?
Regards.
Oooooo, that’s a doosie of a
Oooooo, that’s a doosie of a problem, one that alot of us never thought of, and I doubt that Samsung is even working on that. You did install the ssd’s yourself right? I suppose the only actual way would be to remove the ssd’s (and I know how hard that is on a Macbook, so so sorry) install them on a pc (perhaps there is one you have accesses to, a parent or a friend or even an old dusty rig sitting in storage) and do the update that way. If the ssd is factory installed my apple then apple will be the one sending you the update, but that’s probably not the case. Personally I hate opening up anything apple, whatever I would have to pay someone else to do it would be well worth it.
Now that I think about it,
Now that I think about it, there might be a simpler soloution. Just a guess but perhaps you could do a full backup, format, install windows, update the drive, format, then restore. Still not simple but it might be the easiest answer, if it works, like I said just a guess. The PS one tho, that;s gona need to be put in another system for sure.
A partition agnostic ISO/DOS
A partition agnostic ISO/DOS version of this updater will be out at the end of the month. That should work on everything else, but you really should image / back up those drives first, just in case.
well that just makes every
well that just makes every thing SO much easier, thanks for poking them Allyn. Still no word on vanilla 840’s yet eh?
Just stick them in a pc and
Just stick them in a pc and do the job. It’s a bit of a hassle but it’s for once.
“Just Stick them in a pc” : i
“Just Stick them in a pc” : i do not have any pc and it is also not easy to get the drive off the iMac, since it involves display disassembly on those, so this cant be the solution for Mac users.
Mac updater due out at the
Mac updater due out at the end of the month.
What about people who’ve
What about people who’ve installed this drive on a macintosh?
Thanks for the update
Thanks for the update Allyn.
Any idea if this tool will be available on anything other than Windows?
My main system runs an 840 with Linux, and also have two 840 users with Macs. I can feel some reimaging coming on….
Will be released on end of
Will be released on end of Oct.
Cheers.
Cheers.
Anyone knows whether is
Anyone knows whether is possible to update the firmware by using in a Macbook a second HD where there is installed Windows in bootcamp?