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Plextor M5S 256 GB Review: Marvell Inside, With A Twist

Plextor's Fourth-Generation SSD Family Emerges

If you're old enough, then you probably know Plextor as a purveyor of high-quality optical drives. So, the company's first SSD family (the M1 series) seemed like it came out of left field back in 2010. The M1s were quickly followed by the M2s and M3s, all of which carried on Plextor's tradition of well-rounded, reliable products.

Plextor's next effort launched as the M5 series. Its name seemed misleading, since this was the company's fourth-generation SSD. What happened to the M4? Aside from a conflict with Crucial's already-existing M4 family, the Japanese tend to avoid the number four because it can be pronounced "shi," which sounds similar to the word for death. For that matter, don't expect an M9 series either, as the number nine is pronounced "kyuu" which sounds like the Japanese word for agony or torture.

The fourth-gen M5 comes in two flavors: the M5S and M5 Pro. The M5S is value-oriented. It doesn't come with any accessories or software, and it's only covered by a three-year warranty. The M5 Pro is the performance drive sporting the latest Marvell controller (the 88SS9187). The M5 is faster, complemented by a five-year warranty, and bundled with backup and cloning software, along with a mounting bracket.

Plextor sent over its M5S to start with, and we're taking it for a test drive to evaluate its position versus some of the other popular models in its class.

As can been seen from the table below, the M5S uses the same Marvell processor as the M3 and M3 Pro, and Plextor's 256 GB drives employ a 512 MB DDR memory buffer. The most significant differentiator is that the M5S uses a slower synchronous ONFi-compliant interface, while the other two models utilize Toggle-mode DDR NAND from Toshiba. Despite this, the newer 256 GB drive boasts performance specifications that are faster than the previous generation. We know how Plextor achieved this, and will get into details as we go

Plextor M5S 256 GB (PX-256M5S)Plextor M3 256 GB (PX-256 M3)Plextor M3 Pro 256 GB (PX-256M3 Pro)
ControllerMarvell 88SS9174-BLD2Marvell 88SS9174-BLD2Marvell 88SS9174-BLD2
DDR RAM Buffer Size512 MB (256 x 2)512 MB (256 x 2)512 MB (256 x 2)
NANDMicron 25 nm Synchronous (29F128G08CFAAB)24 nm Toshiba Toggle-mode24 nm Toshiba Toggle-mode
Formatted Capacity238 GiB238 GiB238 GiB
InterfaceSATA 6Gb/sSATA 6Gb/sSATA 6Gb/s
Form Factor2.5", 9 mm Z-height2.5", 9 mm Z-height2.5", 7 mm Z-height
WarrantyThree YearsFive YearsFive Years
Sequential Read    (MB/s)520510540
Sequential Write (MB/s)390360420
4 KB Random Read (IOPS)73 00070 00075 000
4 KB Random Write (IOPS)70 00065 00068 000

Plextor's M5S family includes three drives, and the table below shows us that the performance specs of each model are different. As we might expect, the higher-capacity drives are faster.

In the performance tablet below, numbers in parentheses correspond to the equivalent-capacity models from Plextor's M3 family. Notice that the 64 and 128 GB versions are slower than their predecessors, which is likely the result of a switch to slower Micron NAND.

Plextor M5S 64 GB (PX-64M5S)Plextor M5S 128 GB (PX-128M5S)Plextor M5S 256 GB (PX-256M5S)
Sequential Read (MB/s)520 (520)520 (510)520 (510)
Sequential Write (MB/s)90 (175)200 (210)390 (380)
4 KB Random Read (IOPS)61 000 (55 000)71 000 (70 000)73 000 (70 000)
4 KB Random Write (IOPS)25 000 (40 000)50 000 (50 000)70 000 (65 000)

The prices on 256 GB SSDs continue falling, and are now under $1/GB in many cases. As they become more affordable, we expect that they'll start replacing 128 GB drives in enthusiast machines. We're focusing on Plextor's 256 GB model as a result of this, and because the lower performance of the smaller drives (particularly in sequential writes) makes them less attractive.