Although the M6e does use an M.2 socket SSD, it is actually a PCIe 2.0 x2 SSD. The PCI Express card is used as an adapter for systems that don’t have a motherboard supporting an M.2 socket. The M6e was released because Intel’s 9-series chipsets and therefore no motherboards at the time offered an M.2 socket.

Unfortunately, Plextor is not affording users the ability to detach the M.2 SSD from the PCIe adapter and install it directly into a PCIe slot, at least not without completely voiding their warranty. We took it out and installed it directly onto the Asrock Z97 Extreme6 motherboard but there was no difference in performance as the M6e isn’t fast enough to max out the PCIe x2 interface. Therefore, the only advantage to going this route is to free up space for other PCIe devices such as graphics cards.

Compared to other PCIe products such as the recently reviewed OCZ RevoDrive 350, the Plextor M6e doesn’t require special drivers to work, making it much easier and more convenient to setup. The M6e comes armed with the Marvell 88SS9183 dual-core controller. This server-grade controller is a native PCIe solution which is also being used by the SanDisk A110, a new M.2 SSD that is for the OEM channel only. Along with the Marvell controller is a series of 19nm Toshiba Type A Toggle-mode NAND flash memory that can hit read speeds of 770MB/s. This is the same flash memory that was used on the older M5 Pro model.

As you might expect, pricing isn’t cheap for this high performance SSD. The 128GB model is going for $180 ($1.40 per gigabyte), the 256GB version costs $300 ($1.17 per gigabyte) and the 512GB drive is $550 ($1.07 per gigabyte). The 512GB model isn’t just the best value in terms of price per gigabyte, it is also the fastest. Rated at 700MB/s read and 625MB/s write the 512GB version offers 8% more write performance than the 256GB model. While the read performance is the same, the 256GB model has a write throughput of 580MB/s. That said it’s considerably faster than the 335MB/s write speed of the smaller 128GB model.

Both the 256GB and 512GB models boast random read and write 4K IOPS of 105,000 and 100,000, while the 128GB model offers 96,000 read IOPS and 83,000 write IOPS. All three models support TRIM, S.M.A.R.T. and NCQ as well as AES 256-bit data encryption. They measure 180.98mm long, 121.04mm tall and 22.39mm wide, though the M.2 SSD itself is just 80mm long and 22mm wide. The M.2 specification allows SSDs to be as long as 110mm and as wide as 30mm. The Plextor M6e’s price premium also buys you a lengthier five-year warranty.