Samsung PM841 512GB mSATA SSD Review – Performance and Capacity in a Client SSD


ATTO Disk Benchmark is perhaps one of the oldest benchmarks going and is definitely the main staple for manufacturer performance specifications. ATTO uses RAW or compressible data and, for our benchmarks, we use a set length of 256mb and test both the read and write performance of various transfer sizes ranging from 0.5 to 8192kb. Manufacturers prefer this method of testing as it deals with raw (compressible) data rather than random (includes incompressible data) which, although more realistic, results in lower performance results.

Samsung PM841 512GB ATTO

ATTO Disk Benchmark provided highs of 556MB/s read and 336MB/s write transfer speeds which exceed specifications listed by Samsung.


Crystal Disk Benchmark is used to measure read and write performance through sampling of raw (0/1 Fill/compressible) or random data which is, for the most part, incompressible. In the Samsung PM841 512GB mSATA SSD, performance results are very similar whether we test with compressible or incompressible data and, for this reason, results are displayed utilizing incompressible data.

Samsung PM841 512GB Crystal DiskMark

Typically, Crystal DiskMark results are lower than that of ATTO Disk Benchmark, the reasoning being of course that incompressible data samples are used for testing in CDM. Overall, these are great scores, considering the form factor and capacity of the Samsung PM841 SSD.


Up until recently, AS SSD was the only benchmark created specifically for SSD testing and it uses incompressible data. AS SSD, for the most part, gives us the ‘worst case scenario’ in SSD transfer speeds because of its use of incompressible data and many enthusiasts like to AS SSD for their needs. Transfer speeds are displayed on the left with IOPS results on the right.

Samsung PM841 512GB AS SSD BenchSamsung PM841 512GB AS SSD IOPSA great Total Score is seen with AS SSD as well as a high IOPS result of 90966 IOPS. AS SSD Copy Bench displayed the quality of the SSD as well, resulting in SATA 3 level transfer speeds during the transfer of all three files.

Samsung PM841 512GB AS SSD Copy Bench


  1. Arthur Brownlee IV

    Thanks for the review, was looking to find a good high capacity SSD for my Ultrabook. Looks like I can swoop up the Samsung instead of the Atlas which I was hesitant about.

  2. I’m wondering if this 512GB will be used in the new Samsung Series 900X3E (1080p screen). In USA, NP900X3E-A02US=128GB, NP900X3E-A03US=256GB and there is no trace of 512GB. While in UK, NP900X3E-A01UK=256GB, NP900X3E-A03UK=512GB and there is no trace of 128GB. Totally confusing.

    As of end of April, only NP900X3E-A02US is available at Amazon. I think that I will buy NP900X3E-A02US, then buy and replace by a 480GB Muskin. I hope that the Series 900X3E uses a mSSD and Muskin can fit into it.

    Samsung (like Apple) really overprices the storage as $(NP900X3E-A03US) – $(NP900X3E-A02US) ~ $500 >> expected $1 * 128GB = $128. If you compare, $(NP900X3E-A02US) + $(480GB Muskin) < $(NP900X3E-A03US) !!!!

    Any comment?

    • If you were hoping fot the reviewed drive, isn’t that cheaper than the Mushkin? They sold out within a day but should be restocked and available by end month so stay tuned. Nice systems though but I can’t see Samsung making a 512GB standard as it would cost too much for purchase. We should be happy that they are using their own mSATA SSDs finally…or are they?

  3. Thanks for the review. I don’t see any other large capacity SSDs out there so I’ll be keeping an eye out for when they come back in stock. I presume these would be compatible with most systems? I have a Lenovo Ideapad Yoga 13…

  4. Any chance to get firmware upgrades here? mine isn’t recognized by the Magician software from Samsung.
    (btw. the SSD came with my 900X4D)

    • Any chance to get firmware upgrades here? mine isn’t recognized by the Magician software from Samsung. Funny hitch though having bought it in a Samsung system and still not being able to use it with the Magician. Did Samsung Magician come pre-installed on the machine?

      • No it wasn’t unfortunately… I installed it myself to give it a try. I just read somewhere that the Magician supports consumer SSDs only and it seems like the PM841 isn’t one of those.

  5. Ah and before I forget it, I only get 130mb/s write speed with the 128GB version. Read is around 500mb/s. Windows 8 x64, AHCI mode, Intel Rapid Technology deinstalled,…

  6. Hi, I am currently ordering a MYTHLOGIC pollux 1613-Black. i got and Samsung pm841 256 gb as mSATA, and a Crucial m500 480 gb SSD. and acyually the crucial SSD is the same price as the pm841 512 gb, I read your great reviews on both of them, and i am wondering whether the pm841 512 gb could be better than the crucial as the main drive?
    And is the mSATA pm841 512 gb nearly as reliable or robust as the crucial m500 480 gb?


  7. I’m not exactly sure where the drive is sold. Amazon, ebay, and the samsung website doesn’t seem to be offering the PM841 512GB mSATA drive. My guess it’s discontinued. Any info would be appreciated, thanks!

  8. What about power consumption?

  9. How would you obtain warranty services on a non retail product? I dont think Samsung would support the end user?

  10. im confused… why is the mydigitalssd smart series scores better even tho this samsung one’s AS SSD benchmark score is better than smart series?

  11. Les, Thanks for the review. I was not able to find any information about the SM841 from other sources. Is this a duplicate of the 840 or 840 Pro?

    • The 840 and 840 Pro are notebook drives whereas this is a mSATA. It is not retail and has been next to impossible to get from Day 1. Amazon has them on and off andf there are like 11 in stock right now. Click on our amazon link at the top of this page (SHOP AMAZON) and search Samsung PM841.

  12. this is now the same ssd used by Dell XPS15 NEWEST Model.. It seems to be super fast.. I have the 512 gig with the i7-4702

    • Hi Mike,
      I’m thinking of getting the dell xps with 512ssd. Heard it’s it’s got modest speeds for an ssd but crucial m550 is much better.
      What do you think as I can either get your model or get the one below and swop the 1st drive.

      Any comments are much appreciated.


      • It depends on what you will be using it for Richard. If you haven’t got any plans to puch those SSDs, you will never notice any difference whatsoever. With respect to my choice of the PM841 and M550, there are arguments both ways but the M550 does have power failure protection.

      • Hi Les,

        Thank you for your very prompt reply. Looking at various reviews etc then it seems it’s best to stick with the Samsung ssd and enjoy it.
        Was looking at the crucial ssd as I’ve bought lots of stuff off them and always had a great product.
        In terms of performance, as it’s very little different I’ll stick with the std spec on the xps ssd 512.

        Many thanks again for your help as I stumbled onto this site and it looks very informative.
        Will keep using it.


  13. Hi, My laptop is currently using a PM830…. Can PM841 substitute the PM830?, Are both compatibles?

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