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Assistance - Calling all Samsung EVO owners

Discussion in 'Storage Drives' started by Aurhinius, Aug 5, 2014.

  1. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    Hi all,

    I am looking to collate some information off Samsung EVO owners please.

    I seem to have detected some pretty bad read performance degradation on 2 Samsung EVO 256GB drives that only manifests itself if you delve a bit deeper in to your drives performance.

    I have tested on 2 different drives on 2 completely different spec pc's bought at completely different times. Both drives are used as an OS disk and have had rapid mode enabled for some time.

    I am seeing read transfer speeds on areas of the disk that have been written too as low as 50MB/s!! When tested with HDTune read benchmark. Once the benchmark moves in to empty space the drive returns to your standard 450MB/s.

    So if you have 2 mins to spare download hdtune free edition and run a read benchmark on your EVO. Please only run it on a in use drive with some data on as running on a secured erase drive will only show perfect performance of course.

    Please download and use the Trial version of HD tune 5.50 - The free version has proven to give odd results - This doesn't appear to have effected the original drives issues so this is still a problem

    If you can post a screenshot all the better.

    I have seen one other user post on tomshardware with this issue and wonder if something perhaps in the latest firmware is to blame.

    We shall see!
     
    Last edited: Aug 30, 2014
  2. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    For reference I do not see this behaviour on a heavily used Sandisk SSD on the same PC.
     
  3. Rroff

    Caporegime

    Joined: Oct 13, 2006

    Posts: 49,922

    IIRC the old version of HD Tune (2.55) has some issues with Windows 7 onwards which give weird performance results. Try the trial version of the latest commercial version and it "should" work properly.
     
    Last edited: Aug 5, 2014
  4. wazza300

    Caporegime

    Joined: Jul 11, 2009

    Posts: 26,772

    Location: BenefitStreetBirmingham

    use atto benchmark,it will be more accurate imo

    and or the Samsung magician performance test
     
  5. John24

    Wise Guy

    Joined: Oct 25, 2007

    Posts: 1,297

    My 120GB Evo has had this behaviour since I got it in march. I had not bothered looking into though because perf is still good, startup/shutdown and app launching don't seem affected. It must be haveing some effect though just not enough to be a problem.

    It doesn't seem to be related to used space, or at least it doesn't effect the whole area of used space, I've used 34GB and it happens on the first 20GB. Burst speed is rubbish aswell and if you short sroke it you can see the access time takes a hit on the slow bits.

    [​IMG]

    Never enabled rapid mode and it behaves the same on both an AMD and Intel setup so that rules out hardware and drivers.

    Windows is reporting TRIM is enabled and I tried running the optimise function in the Samsung magician software but it didn't help at all.

    ATTO doesn't show the issue because it creates a file in the free space and tests that. You need something that will test from the begining of the drive.

    I wonder if OcUK have had any returns because of this and if they have had any contact with samsung about it. Seems it's either a firmware issue or just an unfortunate quirk of the drive. I have a few Samsung 830 models that don't behave like this.

    Must admit I'm supprised to see this given samsungs good track record in SSDs.

    [​IMG]

    [​IMG]
     
  6. wazza300

    Caporegime

    Joined: Jul 11, 2009

    Posts: 26,772

    Location: BenefitStreetBirmingham

    mines the same,starts off at 50mb read,then shoots up to 400+ when it reaches 70gb's in

    could be software bug with hdtune,it doesn't feel any slower when using it

    (250gb Samsung evo)
     
  7. Rroff

    Caporegime

    Joined: Oct 13, 2006

    Posts: 49,922

    Seen the same issue with some other drives including HDDs with HD Tune so not really sure what to make of it. (I've one test system where Windows XP + HD Tune works fine but the same discs (30GB SSD and 80GB HDD) when rebooted into Windows 7 exhibit behaviour like that).

    My Evo got to about 50% through the drive with similar to above and then spat out a read error and the whole PC went uber slow until rebooted :| not seen any problems so far in normal use though - I can copy files I know are early on the drive and/or open in a sample program I created and read the contents at expected speeds.
     
    Last edited: Aug 6, 2014
  8. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    Thanks for this guys the more people that can test and report back we can build up a case here.

    It does seem like this is a drive specific issue because as said my sandisk does not exhibit this behaviour with the same version of HDtune so it can't be the HDtune benchmark.

    This investigation by me was prompted by a strangely slow Acronis backup.

    I have used Acronis to image my C drive(Samsung EVO) to D drive (Sandisk).

    When I do this the copy size is approx 50GB and estimated completion time was 40 mins. When I did the calculation of how many MB/s this was I was seeing approx 50MB/s copy speed.

    For an SSD that is VERY bad. When I fired up perfmon and resource mon I could see that the drives were manage exactly that an average of 50MB/s copy speed and queue depth's looked fine.

    Digging further I tested in acronis a copy of D drive (sandisk) to C Drive (EVO) this produced a backup time of 10 mins for 70GB. Checking perfmon and resource mon I was seeing copy speeds at approx 250-300MB/s which is what I would expect for an SSD to SSD copy.

    Testing further if you do a straight windows file copy again you see the same read performance from the EVO capped around the 50MB/s and an order of magnitude slower than the Sandisk to EVO copy.

    So it seems the issue is the reading of data from the EVO drive in sections of the drive that has data on it. Any benchmark I tried i.e AS-SSD bench and copy test, samsung bench etc use spare drive section so report normal performance. With rapid enabled you get artificially inflated scores.

    It's only HDTune that shows this well - haven't tried ATTO or HDtach.

    It's not a benchmark only issue though because as I have said it shows up in Acronis drive backups - Both 11, 2011 and 2014 versions. I tried them all and standard windows copy.

    I have tried with and without samsung magician installed as well and same behaviour.

    So what is going on with this drive... firmware bug?

    Definitely something wrong here.


    Update -

    For my drive it does seem to be the first 75GB of data on the drive. For my second drive which is a bit newer but the same size the problem is limited to the first 30-40GB but spreads out across the drive a bit more with slightly better peaks and troughs.

    Not sure if it is an age related issue which gets progressively worse over time as more data gets written to the same section of the drive but you would expect wear level algoritims to prevent this kind of slow down. It's abnormally slow for an SSD drive read worse than a spinning HDD pretty much.

    TRIM is and always has been enabled.

    Have also checked with rapid enabled/disabled and write cache flushing and no difference.
     
    Last edited: Aug 6, 2014
  9. LordBarrass

    Gangster

    Joined: Apr 22, 2014

    Posts: 338

    We have a return rate off 0.76% for the samsung EV0 840 120GB drive. That is pretty low and these are usually rock Solid. This is the first mention of this issue I have seen. Once you have more info and results let me know and I will pass the details across for them to look into.
     
  10. rotor

    Wise Guy

    Joined: Sep 18, 2012

    Posts: 1,707

    This is not how SSDs work. The disk layout that Windows sees and where data is stored on the physical chips on the SSD are two completely separate things. In a nutshell, every time you write to an SSD, regardless of whether you are overwriting existing data or writing new data (from the operating system's point of view), the SSD actually stores it in a new area and lazily cleans up the old area. This is because data on an SSD can only be written to empty pages, so if the SSD wanted to overwrite an existing page, it would first have to read the contents into a buffer, then erase it, and finally re-rewrite the updated contents of the page. Clearly this has a huge performance impact, which is why it is never done that way. Pages marked as not needed are erased by a background process, and all writes are made to erased pages. If you wrote a script that modified a single 1kB file over and over, you would eventually have written to every part of the SSD. From the operating system's point of view you just re-wrote the same block millions of times, but under the hood the SSD spread those writes over its entire storage space.

    I suspect there is a bug somewhere between benchmark tool/specific drive model/firmware version/SATA controller/etc/etc/etc.

    I have a Dell Precision workstation that bluescreens after resuming from sleep if I use a Crucial C300 SSD (an ancient SSD with theoretically very mature firmware). It took me a couple of weeks of tearing my hair out and trying dozens of different things, before it occurred to me to try a different SSD (a Samsung Evo, specifically), and problem solved! So there are small mysterious incompatibilities that will never fully go away (especially as the market is evolving so rapidly with new standards).
     
  11. rotor

    Wise Guy

    Joined: Sep 18, 2012

    Posts: 1,707

    Further: wear-levelling (spreading writes evenly across every single cell) is CRITICAL to the life-span of an SSD, because each cell can take a very limited number of writes before it wears out and is marked unusable -- the drive has a stockpile of spare cells for this reason. If these drives had a wear-levelling bug, they would be failing in droves, and we would have heard about it.
     
  12. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    Thanks for the info Rotor I was merely corallating HDtune results with what I am seeing on the drive.

    It seems mysterious that we are all seeing really low read performance from these drives when in the first section of the disk first half I would say. How that physically manifests itself in reality I don't know. It would make no sense as per your data distribution for the first part of the disk to provide such bad read performance but for this to correct deeper in to the drive.

    If data is randomly written to individual chips and cells as I agree it actually is you would expect consistant read performance across the drive in the most part?

    It's certainly not the case though.

    Interestingly the write performance of the drive seems solid this is definitely a read performance issue and I encourage everyone to please test and post your results it takes 2 mins to run the test and you can stop it part the way through.

    All we need to see is the initial sections of the drive.

    Have you got any you can test Abarrass at OCuk see if you can replicate the issue?

    I'd like to see this escalated to Samsung to see if we can get an answer. It might be by design and there's something not showing up in the reviews of all these drives but 50MB/s read from a drive that should produce 400-500MB/s isn't good and it's slower than a spinning HDD unit. That's a big problem for me and isn't just limited to benchmarks. I'm seeing this effect backup speeds and file copy speeds.

    Frustratingly I can't test with the old firmware before they added the drive encryption to it.

    So get testing folks and please post your results.
     
    Last edited: Aug 6, 2014
  13. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    More tests done by me -

    HD Tune Pro: Samsung SSD 840 EVO 250G Extra Tests

    Test capacity: 40 gB

    Sequential outer 1354 IOPS 0.739 ms 84.615 MB/s
    Sequential middle 497 IOPS 2.011 ms 31.080 MB/s
    Sequential inner 605 IOPS 1.652 ms 37.840 MB/s


    Cache test -

    Cache
    0.5 MB 307.540 MB/s
    1.0 MB 374.739 MB/s
    1.5 MB 140.910 MB/s
    2.0 MB 133.268 MB/s
    2.5 MB 105.347 MB/s
    3.0 MB 94.682 MB/s
    3.5 MB 94.810 MB/s
    4.0 MB 83.930 MB/s
    4.5 MB 84.106 MB/s
    5.0 MB 76.919 MB/s
    5.5 MB 78.549 MB/s
    6.0 MB 77.862 MB/s
    6.5 MB 76.549 MB/s
    7.0 MB 74.698 MB/s
    7.5 MB 76.576 MB/s
    8.0 MB 79.839 MB/s
    8.5 MB 78.502 MB/s
    9.0 MB 77.004 MB/s
    9.5 MB 77.374 MB/s
    10.0 MB 76.680 MB/s
    10.5 MB 76.512 MB/s
    -----------------------------------------------------------------------

    HD Tune Pro: SanDisk SDSSDHP256G Extra Tests

    Test capacity: 40 gB

    Sequential outer 7432 IOPS 0.135 ms 464.516 MB/s
    Sequential middle 7415 IOPS 0.135 ms 463.436 MB/s
    Sequential inner 7443 IOPS 0.134 ms 465.206 MB/s

    Cache test -

    0.5 MB 345.252 MB/s
    1.0 MB 370.073 MB/s
    1.5 MB 401.771 MB/s
    2.0 MB 345.148 MB/s
    2.5 MB 406.401 MB/s
    3.0 MB 383.858 MB/s
    3.5 MB 424.054 MB/s
    4.0 MB 415.929 MB/s
    4.5 MB 435.463 MB/s
    5.0 MB 429.364 MB/s
    5.5 MB 436.983 MB/s
    6.0 MB 437.196 MB/s
    6.5 MB 440.953 MB/s
    7.0 MB 442.590 MB/s
    7.5 MB 443.842 MB/s
    8.0 MB 446.483 MB/s
    8.5 MB 447.313 MB/s
    9.0 MB 447.493 MB/s
    9.5 MB 450.973 MB/s
    10.0 MB 450.525 MB/s
    10.5 MB 451.576 MB/s

    This is me doing the HDTune short stroking the drives to the 40GB limit.

    Both drive with a 250GB capacity

    Startling really isn't it looking at the response time and speed of the Samsung compared to the sandisk. Both drives are about 50% full. Page file is on the sandisk interestingly enough.
     
    Last edited: Aug 6, 2014
  14. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    A couple of more tests at 2GB drive size

    HD Tune Pro: Samsung SSD 840 EVO 250G Benchmark

    Test capacity: 2 gB

    Read transfer rate
    Transfer Rate Minimum : 23.2 MB/s
    Transfer Rate Maximum : 480.5 MB/s
    Transfer Rate Average : 62.6 MB/s
    Access Time : 0.217 ms
    Burst Rate : 75.2 MB/s
    CPU Usage : 0.3%

    ------------------------------------------------------

    HD Tune Pro: SanDisk SDSSDHP256G Benchmark

    Test capacity: 2 gB

    Read transfer rate
    Transfer Rate Minimum : 321.3 MB/s
    Transfer Rate Maximum : 474.3 MB/s
    Transfer Rate Average : 433.5 MB/s
    Access Time : 0.080 ms
    Burst Rate : 142.8 MB/s
    CPU Usage : 1.2%
     
  15. John24

    Wise Guy

    Joined: Oct 25, 2007

    Posts: 1,297

    abarrass, thanks, there should be enough here to pass on now?

    rotor, your spot on. The only way to a resolution is for samsung to be able to reproduce it I think.

    One more bench, the dips are in exactly the same place as with the two other bench programs.

    [​IMG]
     
  16. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    Another good test John.

    I think there is enough here to ask for samsung to check to see if they can replicate.

    I'm seeing it on two used EVo 250GB, John has a EVO 120GB as does a few other people posting.

    You won't see this on a clean secure erased drive obviously and I am sure secure erasing the drive will restore it's performance but that's not the point is it.

    My EVO is about 50% full with the OS installed and programs/games on both drives I have and two different pc's.

    Keep posting though owners if you can take the 2 mins to do it the more people we can show with the issue the more chance we have of narrowing down what causes this.
     
  17. Aurhinius

    Wise Guy

    Joined: Oct 19, 2002

    Posts: 1,296

    Got pretty similar results as per you John using HD speed but that's what we would have expected.

    e-mailed Samsung support. Suspect to get back scripted rubbish from tier 1 support fingers crossed though!
     
    Last edited: Aug 7, 2014
  18. Doogles

    Mobster

    Joined: Mar 22, 2014

    Posts: 3,047

    Well my Samsung Magician says, Sequential Read is 397mb, Sequential Write 407mb, Random Read IOPS, 66853 and Random Write IOPS 10550. Don't really care because it boots lovely.
     
  19. John24

    Wise Guy

    Joined: Oct 25, 2007

    Posts: 1,297

    That's worrying, I had an SSD (not a samsung) do the same and it went downhill after that, RMAed it and the replacement is still going strong years later. I'd make sure your backed up.

    Aurhinius, keep us updated.
     
  20. Rroff

    Caporegime

    Joined: Oct 13, 2006

    Posts: 49,922

    Doesn't do it with anything else so not sure what to make of it.

    Its "just" a gaming PC so nothing really to backup. Got a fairly decent backup system with a QNAP NAS and external replication for anything critical.
     


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