Samsung SM951 M.2 NVME SSD Review (256GB)


The SSD Review uses benchmark software called PCMark Vantage x64 HDD Suite to create testing scenarios that might be used in the typical user experience. There are eight tests in all and the tests performed record the speed of data movement in MB/s to which they are then given a numerical score after all of the tests are complete. The simulations are as follows:

  • Windows Defender In Use
  • Streaming Data from storage in games such as Alan Wake which allows for massive worlds and riveting non-stop action
  • Importing digital photos into Windows Photo Gallery
  • Starting the Vista Operating System
  • Home Video editing with Movie Maker which can be very time consuming
  • Media Center which can handle video recording, time shifting and streaming from Windows media center to an extender such as Xbox
  • Cataloging a music library
  • Starting applications


After testing, we can see that the 256GB NVMe variant is able to surpass the 512GB AHCI model in PCMark Vantage as well. Here it achieved an overall score of 187,231 points. This time around 5/8 of the test results were over 1GB/s with the highest result reaching 1,645MB/s during the “Windows Media Center” benchmark.  NVMe just keeps getting better by the minute, wouldn’t you say? Samsung SM951 M.2 PCIe NVMe 256GB PCMark Vantage



For our last benchmark, we have decided to use PCMark 8 Extended Storage Workload in order to determine steady state throughput of the SSD. This software is the longest in our battery of tests and takes just under 18 hours per SSD. As this is a specialized component of PCMark 8 Professional, its final result is void of any colorful graphs or charts typical of the normal online results and deciphering the resulting excel file into an easily understood result takes several more hours.

There are 18 phases of testing throughout the entire run, 8 runs of the Degradation Phase, 5 runs of the Steady State Phase and 5 runs of the Recovery Phase. In each phase, several performance tests are run of 10 different software programs; Adobe After Effects, Illustrator, InDesign, Photoshop Heavy and Photoshop Light, Microsoft Excel, PowerPoint and Word, as well as Battlefield 3 and World of Warcraft to cover the gaming element.

  • PRECONDITIONING -The entire SSD is filled twice sequentially with random data of a 128KB file size. The second run accounts for overprovisioning that would have escaped the first;
  • DEGRADATION PHASE – The SSD is hit with random writes of between 4KB and 1MB for 10 minutes and then a single pass performance test is done of each application. The cycle is repeated 8 times, and with each time, the duration of random writes increases by 5 minutes;
  • STEADY STATE PHASE – The drive is hit with random writes of between 4KB and 1MB for 45 minutes before each application is put through a performance test. This process is repeated 5 times;
  • RECOVERY PHASE – The SSD is allowed to idle for 5 minutes before and between performance tests of all applications. This is repeated 5 times which accounts for garbage collection; and
  • CLEANUP – The entire SSD is written with zero data at a write size of 128KB

In reading the results, the Degrade and Steady State phases represent heavy workload testing while the recovery phase represents typical consumer light workload testing.


As you can see, performance is recorded in terms of Bandwidth and Latency. Bandwidth (or throughput) represents the total throughput the drive is able to sustain during the tests during each phase. Latency, at least for the purposes of PCMark 8, takes on a different outlook and for this, we will term it ‘Total Storage Latency’. Typically, latency has been addressed as the time it takes for a command to be executed, or rather, the time from when the last command completed to the time that the next command started. This is shown below as ‘Average Latency’.

PCMark 8 provides a slightly different measurement, however, that we are terming as ‘Total Storage Latency’. This is represented as being the period from the time the last command was completed, until the time it took to complete the next task; the difference of course being that the execution of that task is included in ‘Total Storage Latency’. For both latency graphs, the same still exists where the lower the latency, the faster the responsiveness of the system will be. While both latency charts look very similar, the scale puts into perspective how just a few milliseconds can increase the length of time to complete multiple workloads.

For a more in-depth look into Latency, Bandwidth, and IOPS check out our primer article on them here.


These results show the total average bandwidth across all tests in the 18 phases. In this graph the higher the result the better.

Samsung SM951 NVMe 256GB PCMark 8 Average Bandwidth


These results show the average access time during the workloads across all tests in the 18 phases. In this graph the lower the result the better.

Samsung SM951 NVMe 256GB PCMark 8 Average Latency


These results show the total access time across all tests in the 18 phases. In this graph the lower the result the better.

Samsung SM951 NVMe 256GB PCMark 8 Total Latency

Okay, so we have finally made it to the torture testing round where PCMark 8 likes to write terabytes of data to our test SSDs to show both their heavy and light workload performance. First, taking a look at bandwidth it jumps out at us that this SSD has taken the crown for the highest bandwidth yet, surpassing 400MB/s in the heavy workload phases and reaching nearly 500MB/s during the light workload phases. Next we take a look at latency. While here we don’t see such a dramatic difference as we saw with Iometer, this NVMe variant definitely shows improvement here. It isn’t until we look at the Total Latency graph that we see a clearer picture where latency is about 20% lower during the final recovery/light workload phase.


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    Did the SM951 NVMe throuttle down on high temperature?

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    I thought that using it with a x99 system would be the thing to strive for who buy this expensive ssd and own a z97 system i think that the people that is interested in this ssd already have a x99 or another high end system so in my view it should´t be realeased before this is solved.

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      I am a bit confused as to what your issue may be. Before what is solved?

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        that there is problem with booting with a x99 card (asrock …) yes it may be the motherboard maker that need to upgrade uefi but as i understand the article you only got it to work with z97.

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        I am not sure of which you speak but have been using ASRock boards exclusively for all of my testing of NVMe and have yet to have a problem. the only board we seem to have had difficulty with, and advised quite a few others on actually, is the ASUS boards and booting such drives as the AHcI XP941.

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        Quote”We ran into issues with it in our other test system with an ASRock X99 WS-E motherboard and UEFI version P1.4. While it would boot off the NVMe SM951, speeds maxed out at PCIe 2.0 x2 bandwidth when used in a PCIe x4 to M.2 adapter. When in the same adapter in our Z97 test bench, it performed flawlessly.” from the article above.

        If it works with my Asrock MB i will reconsider (have a asrock x99 m-atx killer) but i didn´t see anything else in the article that made me belive that it will work with my MB.

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        Tell you what… I will get that in my system for a test. Remember, that ASRock motherboard does not have a built in Ultra M.2 adapter.

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        thx you are to kind (according to asrock webpage/manual) i have a ultra M.2 onboard(36Gb)

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        Oooops apologies… The SM951 would work fine in that then as it would be a PCIe x4 slot.

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        yes it is Pcie gen3 x4 slot (M.2)

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        In another article/test you mentioned lower IOPS on Intels X99 Platform compared to Z97 motherboards. Do you have any news to this matter? Is the NVME drive showing similiar behavior? Please put it in your test system and run a quick test, I would really appreciate it.

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    Would you recommend to use Samsung SM951 or XP941 (or which one?) in older dual XEON Supermicro board (X7DWN+) using adapter card (e.g. Bplus M2P4S)? Server with this board is Hyper-V with many small VHDs and lots of backups, so why bother with SSD (requiring more space with worse performance) and not jump right to the M.2? If capacity is not an issue, price
    is worth of performance boost, isn’t it? Thanks for suggestions.

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    Erwin Thierry Klein Haneveld

    where to buy the MZVPV256HDGL-00000 ? can any one give me directions I need the MZVPV NMVE edition

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      you and me both brother, I cannot find one til this day but sure must be a question of time at this point?

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    Christopher Caruk

    Hello, I’ve just been comparing a 512GB 951 NVMe variant that I purchased yesterday with an existing 512GB 951 AHCI. Apparently it’s a sample rather than a production unit but I’m seeing fantastic read speeds but horrific write speeds. In my case I’m using with an Asus Z97i-plus with the latest BIOS. The board identifies the 951 and allows me to install windows (8.1 all latest updates)… so far so good. Unfortunately when I run speed tests against the NVMe variant I get 10 times slower write speeds compared to the AHCI variant.

    CrystalDiskMark: AHCI variant (connected to PCIe 3.0 bus)

    Seq Q32T1 – 1172MB/s read | 1043MB/s write
    4k Q32T1 – 398MB/s read | 289MB/s write
    Seq – 1052MB/read | 900MB/s write
    4k – 35MB/s write | 128MB/s write

    CrystalDiskMark: NVMe variant (connected to PCIe 3.0 bus)

    Seq Q32T1 – 2264MB/s read | 501MB/s write
    4k Q32T1 – 563 MB/s read | 21 MB/s write
    Seq – 1299 MB/read | 170 MB/s write
    4k – 54 MB/s read | 0.98 MB/s write

    Blindingly fast write but horrifically slow write speeds.

    I’ve also tested using the Z97i-plus’s M.2 slot. I see reduced read speeds due to the limited, 10Gbps, speed of the M.2 on this board but the same horrific write speeds (even my Corsair SATA SSD is faster than this).

    Is there something that I might be doing wrong? Could this be a BIOS problem? A Windows NVMe driver problem?


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      Asle Bie Andersen

      Here is the fix!
      I have Sm951 nvme 512GB on Rampage V 🙂

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      What kind of reduced speeds in the M.2 slot are you getting for both NVMe and ACHI? I have the Z97I-Plus also and am wondering what I could expect compared to the professional reviews or if the 10Gbps limit makes the differences between NVMe and ACHI irrelevent?

      Also, did you find a fix for the write speeds of the NVMe variant? Was Asle Bie Anderson’s suggestion the source of the problem?

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        Christopher Caruk

        The recommendation was good but was not the entire cause of the problem. I also found that there was something about the version of Crystal Disk Mark that was distorting the results. Once I used the same version of Crystal Disk Mark as was used in this review, the results were consistent with the results reported here.

        Re the speed… You pretty much max out the M.2 port on the Z97i plus. Regrettably the samsung will perform better than the asus so you are somewhat constrained by the asus M.2 connector. I eventually got the samsung AHCI variant for the M.2 slot and a NVME variant that I plugged into the PCIe slot. The combination is fast… Very fast. So yes, the 10 Gbps limit does make the difference somewhat irrelevant . I suspect that the lower latency of the NVME variant makes it faster but I perceivable so.

        I’m looking forward to trying the new Z170 board with my system and hope that it’s available soon.

        As an aside.. You can boot from either the PCIe or M.2 on the asus z97 using the latest BIOS.

        I have also tried the Asus H97 board but when using to dual boot there is something wrong with the latest BIOS that causes it to replicate boot devices every time you enter the BIOS. It does this until the boot device table fills up and the board will no longer boot at all. So… Avoid the H97 board if trying to do anything sophisticated.

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        Do you happen to have any numbers that you could post of each drive in the M.2 slot and each drive in the PCIe slot?

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        I’ve not done those specific comparisons but I could run a test of the 265GB AHCI in the M.2 slot and the 512GB NVMe in the PCIe slot and post tomorrow, if that would help. One of the problems with having the M.2 onto bottom of the board is that you have to disassemble the system to get at the SSD. In my case I have all of this stuffed into a HD-Plex HS.1. Wonderfully small but tricky to open and close.

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        That would probably help. I could compare that to the numbers in the article and yours above to get a close guess on whether the NVMe is worth waiting/hunting for or just go ahead with the AHCI.

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        Christopher Caruk

        Either way. you will not regret getting one of the 951s. They are by far the fastest SSDs I’ve every used (normal I buy the 850 pros). If it helps… I think that, once the new i76900 and Z170 boards are available I’ll go with a pair of the 512GB NVMe 951s… one on PCIe and the other on the M.2 slot. The new M.2 slots is supposed to be 4x so if the performance is similar I may even try RAIDing them.

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        AHCI will suffice and give you performance you seek, however, consider the makeup of the machine. As Only NVMe is the only true animal built for SSDs, using AHCI is somewhat like putting a Ford engine into a Chevrolet. It may work perfectly and without issue for the long term, however, one simply. Ant beat the native build.

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        I am planning to get the Asus Z97I-PLUS and wondering what should i buy, the Samsung SM951 256GB M.2 PCIe NVMe or the Samsung M.2 (2280) 850 EVO 500GB SATA SSD to plug it in the back of the borad m.2 slot and to install windows on this ssd.

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    Does anyone have any recommendations for a PCIe card to run one of these Samsung drives? I’d love to stick one in my Dell r610 server to run an application server… non business critical so redundancy isn’t needed…
    Bplus M2P4S ? any other recommendation?

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    I got a Gigabyte GA-Z97-UD5H-BK Just learned about this… whats your recomendation for my board… nvme or ahci .. i read somewhere that it does boot to this drive with a little work…

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    Hello everyone, I am building a new skylake pc and the motherboard I bought supports nvme (z170 deluxe). I have my eyes on this small disk but I have also seen the temperature readings during the tests.

    I am planning to buy one as soon as it is available and stick small heatsinks on the memory chips (there are a lot of options on ebay).

    Can the reviewer give some information about the dimensions of the disk and some approximation for the chips (20mm? 14mm?)

    thanks in advance!

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    I am planning to get the Asus Z97I-PLUS and wondering what should i buy, the Samsung SM951 256GB M.2 PCIe NVMe or the Samsung M.2 (2280) 850 EVO 500GB SATA SSD to plug it in the back of the borad m.2 slot and to install windows on this ssd.

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      If you buy the Z97I-PLUS don’t plan on getting the full read/write speeds the SM951 is capable of because the M.2 slot located on the bottom of the board only supports PCIe 3.0 x2. I have the board currently and have checked the specs and other forums. You will still get good speeds around 700 or so. The M.2 EVO gets around 550 so speedwise you would want the SM951 and then upgrade your board later down the road. (There aren’t many ITX boards that support the PCIe 3.0 x4). If you want more storage with decent speeds go for the EVO.

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    Does anyone know when the NVME version will be available to purchase online? thanks

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    How do I get the MZHPV to boot on a desktop with an adapter? I shows up in Disk Management as Disk 0 with an OS on it that I cloned from another drive. But it won’t boot. The BIOS doesn’t see it at all. Help.

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    Where can I buy compatible USB 3.0 case for this drive so I can use it as external drive?

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      Help! I am looking for the same… Now that my XPS has crashed dead, I am looking to read this SSD hard drive externally, but I can’t find any USB cable that’s compatible with this particular M.2 2280 form factor. Anyone knows what manufacturer has finally started selling USB adaptors or enclosures that are compatible with this set of pins?

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    When they will have the M.2 NVMe format 2260 for Laptos and some motherboard ITX?

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    What I mean is that there is no NVnvme 2260 format, which is used by some ITX motherboards and laptops. The 2260 size format does not yet exist on the market

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