Plextor M5S 256GB
M3 and M3 Pro series SSDs feature good specs even by today's standards but the use of Toggle Mode flash memory from Toshiba prevented Plextor from competing with more affordable SSDs. That's why the company introduced the M5S series which can be viewed as a cheaper variant of the M3 with simpler synchronous flash memory with ONFI interface.
The warranty period for the M5S series is limited to 3 years whereas the previous SSDs from Plextor used to come with a 5-year warranty. An adapter for installing the drive into a 3.5-inch bay is removed from the accessories to make the M5S series cheaper.
But the appearance of the M5S is the same as of its predecessor M3. It has a typical case with a height of 9.5 millimeters.
The case is designed in a simpler way inside, though. In M3 and M3 Pro SSDs each chip on the PCB had contact with the aluminum case via a thermal pad, but this thermal interface only remains on the main controller in the M5S.
The PCB is different. Although based on the same Marvell 88SS9174 controller revision BLD2, which works together with a DDR3-1333 SDRAM buffer built out of two 256MB Nanya chips, the flash memory is Micron 29F128G08CFAAB. This is NAND flash memory with ONFI interface which is manufactured on 25nm tech process. Such chips could be found, for example, in the Crucial m4, another popular Marvell-based SSD. The 256GB Plextor M5S contains 16 memory chips, each of which contains two 64-gigabit semiconductor dies. Therefore, the controller can use 4-way interleaving, just like in the M3 and M3 Pro. By the way, considering the use of flash chips with two dies each, there can be no 512GB model in the M5S series.
The manufacturer claims that the change of the memory type doesn’t affect performance. The M5S is promised to be in between the M3 and the M3 Pro in terms of speed. Moreover, these more affordable SSDs undergo the same procedure of 20-hour presale testing at a high temperature as the other SSDs from Plextor. On the other hand, you should be aware that the M5S series has a shorter service life theoretically. Its 25nm flash memory from Micron is rated for 3000 rewrite cycles whereas the Toshiba memory in the M3 and M3 Pro SSDs is expected to last through 5000 rewrite cycles.
Plextor M5 Pro 256GB
So, the M3 and M3 Pro series were followed by the M5S model which in fact delivered the same level of performance at a lower price, thus devaluating both older series. The M3 and M3 Pro seem more reliable, of course, which is also indicated by their longer warranty, yet this is not a strong argument for most consumers. That’s why Plextor needed another product that would be faster than any previous SSD. They have it now. It is the M5 Pro model featuring a completely new hardware platform based on Marvell's newest controller 88SS9187.
The M5 Pro doesn’t betray any sign of its progressive hardware in its appearance. Plextor seems to see no need to change the time-tested SSD case design, so the M5 Pro looks exactly like the M3 Pro. Its brushed aluminum case has a height of 7 millimeters, making it suitable for ultrathin notebooks. The manufacturer’s logo is painted in gray on the face panel of the case. The sticker on the other side offers some service information including part and serial numbers.
The PCB is of course the most intriguing part of the M5 Pro, revealing a number of components we’ve never seen before: a new controller and 19nm flash memory. Oddly enough, the PCB is not only marked as M3S but is identical to the PCB employed for M3 and M3 Pro series. It means the new components are pin-compatible with their previous modifications, so the manufacturer can use the older PCB wiring.
There’s no mistake, though. The PCB indeed carries the highly promising Marvell 88SS9187 chip which is touted by its developer as the first controller for consumer-class SSDs capable of delivering a sequential write speed of up to 500 MB/s. That’s the appeal of the Plextor M5 Pro: with such hardware, it may turn out to be the fastest SSD with SATA 6 Gbit/s interface.
The flash memory employed by the M5 Pro is interesting, too. These are eight Toshiba TH58TEG8D2JBA8C chips which feature MLC NAND devices manufactured on the most progressive 19nm technology. Each chip contains four semiconductor dies with a conventional capacity of 64 gigabits. So, just like in the previous products, the M5 Pro's controller can benefit from 4-way interleave on each channel. The key advantage of Toshiba’s 19nm chips is that they help make the end product cheaper but they do not offer any other benefits. Its Toggle Mode interface has the same bandwidth and its service life, according to the manufacturer, is no different from that of 24nm flash.
Besides the Marvell 88SS9187 controller and 19-nm Toggle Mode MLC NAND flash, the Plextor M5 Pro has a SDRAM buffer. The buffer is the standard size for Plextor SSDs: two 256MB DDR3-1333 SDRAM chips from Nanya.
Being a premium-class product, the Plextor M5 Pro boasts a 5-year warranty and comes with a complete set of accessories including an adapter for installing it into a 3.5-inch bay. Although targeted at enthusiasts, the M5 Pro has some properties intended for corporate users such as AES encryption with a 256-bit key. Data integrity is ensured by means of 128-bit ECC which is supported by the new Marvell controller.