Plextor M5M mSATA SSD Review (256GB) – The M5M Displays Incredible PCMark Performance


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.

Plextor M5M 256GB mSATA SSD ATTO

Specifications listed 540MB/s read and 430MB/s write transfer performance and ATTO is very close to that. ATTO represents the easiest in data transfer as it uses highly compressible data and testing with highly incompressible data will paint a better picture.


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 Plextor M5M 256GB 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.

Plextor M5M 256GB mSATA SSD Crystal DiskMark

Typical of Crystal Diskmark, performance drops just a bit, however, we need to consider that we are testing with random, or highly incompressible, data samples. This is an excellent result even with the low 4k random write result a bit lower than normal.


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.

Plextor M5M 256GB mSATA SSD AS SSD BenchPlextor M5M 256GB mSATA SSD AS SSD IOPSWe always hope to see the AS SSD Total Score above 1000, however, our first look at read and write 4k-64Thrd IOPS results is very encouraging. With IOPS like this, we might see some excellent PCMark Vantage transfer speeds.

Plextor M5M 256GB mSATA SSD AS SSD Copy Bench

The AS SSD Copy Benchmark creates 3 files that we might see on a normal basis (ISO/Program/Game) and transfers them from one spot on the SSD to another, keeping track of the maximum transfer speeds reached and the time it took to transfer the files. This result shows excellent SATA 3 results when moving the ISO and Game but the Program transfer left something to be desired. We repeated the test three times to ensure the first test result wasn’t a fluke. All were consistent.


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    Thank you for the review! I know it’ll be an unfair comparison but I was wondering if we can compare this mSATA SSD to a Samsung 840 Pro since it’s in the same price range :).

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    “Although the total RAW memory totals 256GB, and this is the advertised capacity, formatting of the M5M does leave the user with a total of 238GB of available storage space”
    You mean 258GiB?

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      No. I mean GB (gigabytes). Every now and then someone always seems to throw in this same curve which is pretty simple to understand. The total available storage space is 238GB (gigabytes) and can be easily observed by looking at any of the benchmarks that reflect storage space. GiB has absolutely no space in the consumer arena and, actually, should flat out be done away with as it draws a line of confusion that really isn’t necessary. Why lose the understanding of the typical person though right? Thanks for taking the time to read our reports though…appreciated.

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        I believe it is actually 238GiB formatted capacity. Windows Explorer of course will say that the capacity of the volume is 238GB but it’s a lie because if you convert 250GB into the units of GiB, then it is 238GiB unless it’s a coincidence that formating reduces capacity to 238GB from 250GB.
        Microsoft should really fix Explorer so there won’t be any more confusion, like by using base 10 since there units are base 10.

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        man what u askin ? that’s been decades that drives has less size after installing and formatting .. this is old school mate

        Base10 Base2 Base10 Base2
        36GB 34.3GB 160GB 152.6GB
        40GB 38.1GB 200GB 190.7GB
        73GB 69.6GB 250GB 238.4GB
        80GB 76.3GB 300GB 286.1GB
        100GB 95.4GB 500GB 476.8GB
        120GB 114.4GB 750GB 715.3GB
        146GB 139.2GB 1000GB 953.7GB

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        Yes it has less size after formatting and it looks like your conversions from base 10 to base 2 are correct.

        But before formatting, a 1TB drive will have more than 953GiB of total storage and more than 1TB of storage. After formatting it’ll have 1TB or 953GiB of storage.

        The advertised storage of a hard drive is the storage space available after formatting.

        A volume that has 1MB of storage, will have 1.048576MB of storage before formatting, according to the disclaimer on WD’s site. At least I think that is what they mean.

        As used for storage capacity, one megabyte (MB) = one million bytes, one gigabyte (GB) = one billion bytes, and one terabyte (TB) = one trillion bytes. Total accessible capacity varies depending on operating environment. As used for buffer or cache, one megabyte (MB) = 1,048,576 bytes. As used for transfer rate or interface, megabyte per second (MB/s) = one million bytes per second, megabit per second (Mb/s) = one million bits per second, and gigabit per second (Gb/s) = one billion bits per second.

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        Hi yeah bcos partitioning takes some space MBR or GPT
        And now days win 8 takes even more there is some MB for recovery partition then EFi partition 100MB

        for 1TB is 953,674 MB and windows output is 931 GB

        here is good expl.

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    Thanks for the review. I just got one of these because it was the only one sold at my local MSY in Canberra. They’re $239 here in Australia, and worth every cent. I can now use those valuable drive bays in my laptop for storage and have this tiny form factor OS drive. Pity it’s only SATA2 on board though and requires a convertor to get the SATA 3 speeds. I’m sure I won’t notice the difference.

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      Defo there will be notice .. depend what u will be doing .. if u have only SATA II then u should buy cheapest msata or normal SATA II SSD tho

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    Hi Les,

    I have a Lenovo Y580, with a 64GB caching SSD and 1 TB 5400 HDD. Planning to replace the SSD with bigger volume one for the OS and photo editing programs like Lightroom and Capture NX2, and perhaps might put in a 7200 HDD for storage.

    Of course I want speed, but I also would like stability, reliability. As far as volumes is concerned, my preference goes out to a 480GB mSata module, but perhaps a 240GB / 256GB might also do.

    Money is not an issue up to 512 GB, so what would you recommend in terms of stability (i.o.w. best for data lost protection), Crucial M4 256 / Crucial M500 480GB / Plextor 256 GB / Intel xxx, and still have reasonable speeds?



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    I just got 2×256 of these nice SSDs .. waiting for SATA adapter to connect second and will be creating RAID 0
    Will be lightning speed !

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