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