Samsung SM951 M.2 SSD RAID Review – Over 4GB/s and 300K IOPS A Consumer Option


Crystal Disk Benchmark is used to measure read and write performance through sampling of random data which is, for the most part, incompressible. Performance is virtually identical, regardless of data sample so we have included only that using random data samples.  Further, we are using the newest release of CDM where the queue depth, and even thread count, can be set.  Take a look what doubling threads and increasing the QD to 512 does on the right.  Amazing speed!

SM951 512GB RAID0 Crystal DiskMark NewSM951 512GB RAID0 Crystal DiskMark Last

Crystal Disk Mark enables us to manipulate our testing of the random data and pushing performance above 4.3GB/s demonstrates just how well this SSD scales.


The toughest benchmark available for solid state drives is AS SSD as it relies solely on incompressible data samples when testing performance. For the most part, AS SSD tests can be considered the ‘worst case scenario’ in obtaining data transfer speeds and many enthusiasts like AS SSD for their needs. Transfer speeds are displayed on the left with IOPS results on the right.

 SM951 512GB RAID0 AS SSD BenchSM951 512GB RAID0 AS SSD IOPSWe were more than happy to see that the Samsung SM951 RAID stood up to one of the toughest benchmarks available today, but more importantly, check out those IOPS at 315K read and 148K write.  That is something special.  Better yet, look at the data transfer speeds in this Copy Benchmark:

SM951 512GB RAID0 AS SSD Copy Benchmark

Transfer speeds such as seen here are seldom seen in our testing and never seen in typical consumer report.  An actual disk transfer speed confirmation of 2.1GB/s is nothing to scoff at.


Anvil’s Storage Utilities (ASU) are the most complete test bed available for the solid state drive today. The benchmark displays test results for, not only throughput but also, IOPS and Disk Access Times. Not only does it have a preset SSD benchmark, but also, it has included such things as endurance testing and threaded I/O read, write and mixed tests, all of which are very simple to understand and use in our benchmark testing.

SM951 512GB RAID0 Anvil

Although speeds are a bit lower in Anvil and with respect to both throughput and IOPS, it is a great utility to get a look at access speeds, and the overall picture.


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


The PCMark Total Score of the Samsung SM951 RAID0 combination is 145340 with a high transfer speed of 1.4GB/s while working in Windows Media Center. Looking closely, we see that 5 of the 8 tests resulted in data transfer speeds over 900MB/s.

SM951 512GB RAID0 Vantage


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    Eduardo Solanas

    I would like an article comparing real life tests if it is worthy a PCIE SSD or a SSD for example.
    What should we check in the benchmarks, random reads if what we want is a faster SO ? I don´t plan to move big files, I just want to have a quicker SO and an instant load of the games/levels, etc

    Any advice ? I want to buy a SSD but I want to know if it is worthy to have a NVME SM951 plus a new motherboard to support NVME boot or a Samsung SSD 850 pro ?


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      Sorry been a very long day… ‘SO’ ??? From what you seem to speak for taskload, I am not sure there would be a difference in either SSD.

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        Eduardo Solanas

        Yeah I mean SO load time, opening apps, loading game maps etc this kind of things would that make a real difference a Samsung SM951 NVME PCIE vs a Samsung 850 pro ?
        I thought high IOPS means opening apps load the system faster, and PCIE ones almost double the SATA SSDs

        If does not make difference then 850 EVO or 850 Pro any advice ?


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        Even an expert wount be able to differentiate between such as it is strictly disk access for start-up and application loading. Game maps I may have Sean comment on as he is more of a gamer and it seems logical that you might see a bit of a quicker load time there. To this point, however, I havent seen that as a common test metric as there are so many influences that can affect the result from one machine to the next.

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        Every single time I look at a SSD review my eyes go straight to the 4K QD1 speeds. It is my understanding that the 4K read/write is where you will most notice performance (higher 4K read/write speeds = faster OS operations). I do not discount response time and I am aware that high sequential speeds greatly benefit professional workloads but I am never as impressed with these (insanely high) GB sequential speeds as I am with 4K speeds. When SSDs first gained popularity the 4K speeds for read were around 16MB/s but now the high performers get around 50MB/s. This is not too impressive of an increase in 4 years as has been the sequential speed increase. Why is it that 4K speeds have only crept up so slightly?

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        Lubomir Zvolensky

        It is matter of application, optimizations, latencies, user mode->kernel mode switches, operating system stacks, hardware controllers used in SSDs, their sheer number, number of channels available to NAND, firmware optimization etc, etc.

        My take : number of channels from SSD controller to NAND and internal SSD latencies take the biggest role. Check out how many channels you have available on latest Intel P/S series and what kind of 4K QD1 performance they achieve. With the same operating systems and the same other deficiencies as all other SSDs are tested… yes I know, there is a price. Bentley ain’t cheap either.

        I also second opinion of RickH above dealing with ATTO performance results for 1024k, 2048k, 4096k and 8192k block sizes posted on page 2 of this review : there is clearly 32bit integer used for variable storing that result, so it simply overflows after 4GB/s what exactly is 4194304 bytes per second. So actually the performance results are:

        1024k writes : 3165823 reads: 4194304+201326
        2048k writes : 3138424 reads: 4194304+223253
        4096k writes : 3165823 reads: 4194304+223253
        8192k writes : 3165823 reads: 4194304+212097

        well, that’s almost 4.4GB/s in “decimal” format. Just wow. Yes, not that important in real life, but still wow for a chewing-gum size. Guys, this is maxing out PCI-Express 3.0 4x bandwidth, did you realize ? It probably wouldn’t go much faster even when connected to 8x slot as performance doesn’t get significantly better after 256kB blocks, all in all this is phenomenal result. How many NAND chips are on that board ? Next to none. Imagine SSD with 16 such chips and sufficient channels to get to them.

        There is no PCI-Express or any other bus today that could transfer that much data 🙂 PCI-Express 3.0 8x maxes out at 6.4GB/s (8GB/s theoretical throughput as each lane is 1GB/s).

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        I think “SO” is spanish for OS . . .

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    Wow! really … really impressive speed!

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    The ATTO read results aren’t so strange… it apparently uses an unsigned 32-bit integer for the speeds, in KB. You went so fast you overflowed. You can probably adjust for that and get the correct high-end speeds by adding 4194304 (2^32/1024) to each. The ATTO author never expected it to ever see speeds like these!

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    Review states M2 PCIe 2.0, but I’m assuming that’s a typo and you meant 3.0 X4?

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    How did you configure the RAID 0 with NVMe PCIe/M.2 SSDs? Windows included software raid?

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    ” It can only be accomplished with the ASRock X99 Extreme 11″

    actually if you pop a 2nd SM-951 in the Extreme 6’s 2nd PCIe 3.0 slot (via e.g. the ~$30 Addonics M2 adapter) it’ll be at 4X, equivalent to the 2nd Ultra M.2 port on the 11.

    Nice thing too is that the CPU’s lanes will be all used up, 8 to the GPU and 8 to the SM-951s . . . I don’t understand why only ASRock jumped on the “Ultra” bandwagon, it should have been obvious last year this was the way to go . . .

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    Hey Les – always admire your work. Quick ? though – I was not ever able to run Samsung Magician with RAID’ed Samsung SSDs. It just does not recognize them – any version including 4.6. Were you able to do so or I’m misinterpreting some of the screenshots?

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    Is it possible to raid a pair of SM951 with one on the M.2 slot and the other one on a PCIe 3.0 adapter? My MB has only one M.2 Slot (MSI X99A SLI PLUS)

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      Yes, it should be possible. You may need to update your motherboard BIOS. Also, as far as I understand, the RAID on x99 is limited to a software RAID, so you won’t be able to BOOT from the array, BUT there might be some fancy setup going on here with this specific AsRock x99 Extreme11 motherboard with its integrated LSI storage controller that could make booting from it possible. I wasn’t able to find that info though.

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    I am building my first pc and am not too familiar with PCIe lanes. My motherboard is a MSI z170a gaming m7. If I raid two SM951 in the m.2 slots, will it use the 16 lanes from the standard PCIe slots?

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    Just wondering how was the CPU usage? RAID 0 is usually super low but these are some crazy transfer rates.

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