Samsung 840 EVO SSD Read Performance Degradation #2

It’s not a secret that data that sat unmodified for a period of months on a Samsung 840 EVO SSD drive, could no longer be read at full speed. In an attempt to overcome the issue, last year Samsung released a firmware (ver. EXT0CB6Q ) which was supposed to keep the 840 EVO drives at full speed, however, it turned out otherwise as the same issue began ailing most of the EVO drives once more.

For starters, let’s take a look at my SATA-2-bound Samsung 840EVO 120GB RAID0 array performance in HD Tune. If you’re interested in seeing more HD Tune benchmarks of the array and its performance drop over time, check out my other post here. The array hasn’t been refreshed since 24th December, 2014, meaning, the data has been “degrading” for almost 4 months now. Just as expected, the results are disappointing to say the least (pic. 1).

hd tune 2015-04-16

Picture 1

A few days ago,  the 24th April to be exact, Samsung released a new firmware (ver. EXT0DB6Q) addressing the notorious old data read issue among the Samsung 840 EVO drives, however, I’ve read the new firmware is more of a workaround rather than a real fix to a problem as it keeps periodically refreshing the old data by itself. Anyway, the easiest and probably the safest way to upgrade your 840 EVO SSD firmware is via the Samsung Magician 4.6 software as long as you are not in RAID mode. If you happen to run your SSDs in RAID mode, Samsung Magician software is unable to detect it whatsoever and this is where I hit a snag with my RAID0 array.  Without digging into peculiarities of updating the RAID array at once, which I’m not sure if it’s even possible, I’m going to  go the easiest way and break down the array and then update each SSD drive separately on a separate computer.


Picture 2. A new firmware highlighted in red

 Since I’m not sure how long it’s going to take for the new firmware to “fix” the old data blocks on my RAID0 array, I’m just going to run the DiskFresh utility to put my EVOs in the best shape possible. The utility rewrites all the sectors in use and thus restores the drive’s performance to its peak. Having done that, we get a great starting point in monitoring the new firmware efficiency when it comes to old data for the time to come (pic. 3). I’m going to keep a close eye on the matter in the months to come and post the news here. Keeping my fingers crossed it turns fine this time.

Picture 3

Picture 3.

Update 31st May, 2015

It’s been a month since my SSDs were updated to the EXT0DB6Q firmware and finally there’s some good news as the performance hasn’t degraded a single bit. In fact, it has slightly improved. As seen in picture 4, the blue performance curve is flat just as it should be on a decent SSD and no longer resembles an erratic heartbeat rate of a student called up for recitation as seen in picture 1.

Picture 4

Picture 4.


Update 27th July, 2015

It’s been another two months since the firmware update and things are still looking really good as seen in picture 5 below. The performance of my RAID0 array hasn’t degraded a bit and stayed stable as it is supposed to. Once again, I’m not sure how the new firmware addresses the aforementioned issue and it could be just a workaround, I think it’s time to forget the bumpy past call it a day. Finally.

Picture 5.

Picture 5.

Samsung 840 EVO SSD Read Performance Degradation #1

Sadly enough, the old data read issue has been present on the Samsung 840 EVO series solid state drives since their initial release in 2013. The bug appears in the form of constant old data read performance degradation over time, meaning, the older the files on the 840 EVO drive get, the slower the drive will read them. However, if the old drive content is freshly rewritten, the read performance will be at its peak for some time before it starts to decay again.  Samsung was well aware of this issue and its attempt at fixing it was the release of the EXT0CB6Q firmware, however, most users are reporting the aforementioned problem is still ailing the 840 EVO series solid state drives.


Picture 1

 I have been running two Samsung 840 EVO 120GB drives in RAID0 configuration for a few moths now, long enough to be able to share my read performance results with you.

Test setup: ASUS P6T Deluxe / Intel Xeon X5670 / 12GB 1600MHz RAM / 2x120GB Samsung EVOs. Please note I am running quite an old motherboard lacking the SATA3 support, which means I am limited to only SATA2 speed. Ideally, I should expect the read speed of up to ~600MB/s            (300MB/s x 2 because of RAID0).

Before I begin testing the performance of my RAID0 array, here is the screenshot ensuring both drives are healthy as well as on the latest firmware, the EXT0CB6Q (pic. 2).


Picture 2.


Back in December of 2014, I ran the DiskFresh utility to fully restore the drives read performance and I have been monitoring it since. The array has 160GB of free storage space. Let’s take a look at the read performance in HD Tune, shall we?

hd tune full

Picture 3. HD Tune

As seen in picture 3, the integrated SATA2 controller is capable of sustaining the read speed  of 540MB/s on average in RAID0. Maximum and minimum speeds are pretty close to the reported average, which is good news. One month later (31st , Jan.) things start to look a bit worse. Although the average and maximum speeds did not change much, the minimum read speed is another story here as it went down from the respectable 494MB/s to 382MB/s in just a moth’s time. If you pay heed to the speed graph, the second run looks much less consistent compared to the first one. The last, third run is the reason I decided to compile this post on my blog. You can see the average and minimum read speeds went down even further and hit  the record low of 410 and 115 MB/s respectively. Not to mention, the graph has become extremely inconsistent and shameful to look at in just two months’ time.

Speaking from a real-world performance standpoint, all I have noticed is Windows 7 now takes about 14 seconds to boot in comparison to 10-11 seconds it would take in December, 2014. Although ~3 seconds does not seem like a long period of time, it actually accounts for a whopping ~30% of increase! That being said, I am still reluctant to run the DiskFresh utility every two months or so, as frequent SSD content rewrites do take a bad toll on the TLC-based drive’s longevity.

The good thing is Samsung has reported to be working on a new firmware update addressing the issue, which, hopefully, turns out fine this time.

Update 2nd April, 2015

It has been another month without a firmware update addressing the old data read speed degradation issue and it looks like the speed has gone down big time. Twice to be exact.