Plextor M6S SSD Review (256GB) – Strength in a New Marvell SSD Controller Offering

It has been a long time in the making but the new Plextor M6S family is finally rolling out.  Based on Marvell SSD controllers and Toshiba NAND flash memory, we got our first glimpse at the M6e M.2 PCIe X2 SSD some months ago in our IO-Switch Raijin Review, followed by our official analysis of the 512GB capacity M6e (and some great RAID testing) a short time ago.  To be completely honest, we have been just a bit spoiled by all manufacturers with respect to our M.2 SSD coverage.  Things are a bit different today, however, as we introduce the Plextor M6S SSD, the newest of the Plextor M6 family and with a brand new Marvell controller.

Plextor M6S 256GB SSDOpener

Traditionally, Plextor has remained loyal to their allies and you won’t be seeing any controller but Marvell, or any memory but that of Toshiba, in a Plextor SSD any time soon.  These are deep-seated partnerships and may even be the reason that Plextor has enjoyed such success, avoiding some of the speed bumps experienced by other manufacturers as SSD technology matured.  The advantage of remaining with set components allows your engineering team the opportunity to specialize just a bit more in what they are best at.


The Plextor M6S is a SATA 3 2.5″ form factor SSD that is 7mm in height.  It will be available in capacities of 128, 256 and 512GB, with the mSATA version (M6M) being released with same capacities, along with the added 64GB.  Check out our Plextor M6M 256GB mSATA SSD Report at our sister site, Technology X. Performance of the M6S is variable, depending on capacity, with all sizes rated at 520MB/s read disk transfer speeds.  Write transfer speeds are listed at 440MB/s (512GB), 420MB/s (256GB) and 300MB/s and max IOPS for our 256GB sample are  listed at 90,000 IOPS read and 80,000 IOPS write.

Plextor M6S 256GB SSD Standing 2

MSRP for the M6S is $139.99 (128GB), $249.99 (256GB), and $499.99(512GB) and these prices also reflect that of the mSATA Plextor M6M SSD.  M6 features also include True Protect which incorporates 256-bit AES encryption, True Speed in-house firmware that maintains SSD performance over time, and the M6S comes with a three-year limited warranty.

Plextor M6S 256GB SSD Exterior FrontPlextor M6S 256GB SSD Exterior BackCOMPONENTS

The Plextor M6S is encased in a two piece aluminum shell that is secured by four screws on the sides of the SSD.  One of the screws is covered with a security sticker that would void any warranty should it become damaged while taking a peak inside the SSD.

Plextor M6S 256GB SSD FrontPlextor M6S 256GB SSD BackInside the shell is a green printed circuit board (PCB) that contains the Marvell controller, eight packages of memory and one module of DRAM cache memory.

Plextor M6S 256GB SSD PCB FrontThe controller used is the Marvell 88SS9188 four channel controller and this is the first time we have seen it.  We might bet that it has a great deal in common with the 88SS9189 that has appeared in  the Micron M550 and ADATA SP920 SSDs most recently, our reasoning primarily following the lines of performance similarities when examining the IOPS specs.

Plextor M6S 256GB SSD Marvell 88SS9188 Controller

There are eight modules of Toshiba 19nm MLC Toggle Mode NAND flash memory on the front of the SSD with the back being void of components.  Each module is 32GB in size and we might bet that there would be an additional eight modules of this exact memory on the bottom of the PCB if this were to be the 512GB capacity.  Also on the front of the PCB is a Micron DDR3 512MB DRAM cache memory module.

Plextor M6S 256GB SSD PCB Back


  1. blank

    Nice to see another player in the arena.

    BUT i can’t help to find them overpriced and somewhat slow.
    I appreciate their good name in reliability but that argument is steadily losing ground
    nowadays with even OCZ’s latest offerings being quite reliable.
    Samsung, Intel, crucial all are reliable and is just so many options.

    Plextor needs to realize that the days they bested sandforce in almost every aspect,
    are long gone and price their ssd’s accordingly.

  2. blank

    This time Plextor quite fails .. even on anandtech M6M and this has low performance .. ? and few months back it was one of the best ?
    I really dont understand your tests it is all bollocks

    • blank

      No man it’s not all “bollocks”…
      It’s just that every ssd is so fast now that you won’t pretty much feel the diffrence
      between this and 840/vector when your case cover closes.
      Reliability and Value are the top factors now and at least a silver budge is justified on this.
      Although as i said before Value begins to be THE factor now.
      And yes sometime before M5P Extreme was one of the best in all departments including performance, so why are you asking??

      • blank

        Well the way of reviewing ssds should be changed .. people gets confused missunderstood
        On that anandtech web they pretty much SLAGGING m6m ..
        Their tests are completelly useles wrong. Drives espec. Ssds shouldnt be tested this way ..
        Most important is real world use

      • blank

        I don’t understand you, why the tests are wrong?
        He uses all the best and most recognized tools for ssd benching.
        These tools are designed to show you diffs in performance that in real world usage are almost invisible.
        Like i told you real life use is the same in ssds in our days. To show a graph where office instals 0.3ns faster in one drive than another is pretty much useless.

      • blank

        Yes that i knew long time ago mate i have 10 different ssds
        What am trying to say these tests are too much in depth which is not how should be
        You lokking at miliseconds .seconds and that end user will NEVER register
        It is useles and then when ssds are compared is such depth the differences are revealed and as people are naive once they see such negativness in review it will pull them out to choose or buy that product ..
        For example read and write speeds will never go higher than 500MB SATA III is advertised as 600MB but treshold is somewhere btw. 500-550
        And about 4k some perform less some bit more but difference in reality is never registered when u behind pc .. the such in depth review of ssds is waste and driving people not buy it
        But in other way best ssd is the cheapest one .. and more people goes this way

      • blank

        Well, there are people that actually need every IOPS, so such reviews actually matter to tham. You don’t have to read the review, if you don’t like it.
        Also, testing real world ssd performance is quite hard (and possibly inconsistent), thats why nobody does it anymore.

      • blank

        Benjamin covered me but i’d like to add a question.
        What do you suggest is the best way to test them?
        Maybe with your logic we shouldn’t test them at all and just have a price catalog?
        Sorry man, you have some points but you can’t come in an enthusiast community and ask for less info on the products…

      • blank

        Well keep testing as it is but at the end of review show that reality is that difference btw ”best benchmarked” ssd is very small ..
        You know I had installed 6 brands SSDs and with Win experience index the score was always 8.1 or 8.2 means difference is minimal

      • blank

        I am a bit confused as you seem to state one point and then go to another by stating that the tests are too confusing…
        From our perspective… The question as to how we test is an ongoing topic and we have decided our means of testing over much conversation, just like this. If you look at our enterprise tests, they differ significantly from consumer testing.
        Having said that, real world testing is a nice add on but what is valuable to one is useless to another. Conversely, websites with their own ‘testing format’ still do the same as others that elect to use simple programs such as ATTO, AS SSD, Crystal, Anvil and PCMark. In the end, we test performance by transfer speeds with both compressible and incompressible data. You can color coat that any way you wish with your own fancy dancy testing software but regardless…the same result is accomplished.
        From our perspective, we want to test consumer SSDs at the consumer level and we want the typical consumer to understand. It is an added benefit that we test with software that you can test with because many use this software to compare and ensure their SSD is working properly. Not every reviewer will agree on every SSD but, let’s face it, this SSD has premium memory, a great processor, reputable DRAM cache and is a key entry for a specific crowd.
        In the end, if all reviewers had the same report and opinion of a drive, that would take away what is best about the independence of being a reputable review site. Let me list two very specific examples that we differed greatly from the rest of the world. The first was with the Samsung Series 9 where we identified SEVERE wifi problems well after so many said this was the new age in ultrabooks. The second was with respect to Seagate Momentus XT where we stated time and time again that no visible performance was observed…So many others thought this was the best thing since sliced bread.
        It brings me way back to when we were the first to post that page file should be shut down with SSDs as well as auto system backusp…. not everybody will ever agree but the independence of thought is paramount.

      • blank

        Well said Les.
        Keep up the good work!

      • blank

        Hi Les, I think that controller has only 4 channels and not 8 can you clarify that. I’m getting conflicting info.

      • blank

        You are correct. We never had the pdf available to us at that point in time and received different information obviously.

  3. blank

    So the idea is to give every single drive an award so that people buy it with your amazon links? This drive was universally “meh” on every other site, but i see every single drive here gets an award and an sponsored amazon link.

  4. blank

    Excellent review Les!

  5. blank

    Is the sequential transferrate equal from begin to the end? To much manufacturers cheating in that case (Samsung Evo, Toshiba Q-series)

    • blank

      Explain please… do you meanas file size progresses or through a times transfer?

      • blank

        The Evo and Q-series “cheat” because both use for a limited time a SLC-mode. The Evo can hold for some seconds about 500MB/s and then it drops to about 250MB/s (250GB-version). The Toshiba write 50% with over 450MB/s and then drops to <100MB/s because it wrote the 1st50% in SLC-mode and then it writes to second bit of the NAND

        Benchmarks like AS SSD, Crystal Disk Mark and Atto wrote to less GB to show this behaviour

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