One thing that has remained pretty constant since SSDs started to appear, is that the storage interface they connect to appears to struggle to keep pace with the performance levels of the SSD.
The SATA2 interface was soon saturated by the SSDs of the day, and SATA3 hasn’t done much better. If we look at mainstream PC platform chipsets such as the Intel Z68, Z77, Z87, and now Z97, they all have one thing in common. You have the high speed ‘north’ side of the board where the CPU, memory, and PCIe3 reside. PCIe3 connects direct to the CPU, and has 16 10Gbps lanes available for graphics cards or PCIe storage.
The ‘south’ side of the board where the platform controller hub (PCH) sits is very much slower, and restricted to PCIe2 speeds. In actual fact you have 8 PCIe2 lanes with 5Gbps bandwidth per lane. The PCH not only hosts the SATA interface but also all the other connected peripherals that are required in order to allow the PC to function, such as LAN, USB, and audio.
The Intel Z97 chipset supports M.2. and SATA Express natively, but uses only two PCIe2 lanes, and these are shared between M.2. and SATA Express, and have a maximum bandwidth of 10Gbps. That would give up to 1GB/s available bandwidth without overheads. With overheads that will drop down to around 780MB/s, which isn’t a vast improvement over SATA3 speeds. Nevertheless, that is all that’s available via this revision of the PCH on Z97. It is rumoured that the Intel 100 series chipset, designed for the Intel Skylake CPU will make the transition to PCIe3 for the PCH, which will double the amount of available bandwidth at the ‘south’ side of the board, but Skylake is more than a year away.
It could be that to properly support future SSDs, the storage interface will have to move to the ‘north’ side of the board. This seems quite simple, you can use one of the PCIe3 x16 sockets for a PCIe SSD such as the OCZ RevoDrive 350, or wait until NVMe SSDs start to appear in mainstream form. The problem with this approach in a mainstream PC is the fact that PCIe3 is generally used for graphics cards, and I can’t see gamers giving up graphics bandwidth for storage, plus you only have 16 PCIe3 lanes available.
With the next generation of CPUs dropping to a 14nm fabrication process, that will give more room on the CPU die for more components, and it would make perfect sense to me for Intel to add a high speed storage interface to the CPU itself. This won’t happen with Broadwell, and from what I know about Skylake it won’t happen there either. So that leaves PCIe3, M.2., or SATA Express for the immediate future.
That neatly brings us to the point of this article. In this review I will be checking out an M.2. PCIe SSD in the shape of the Plextor M6e M.2., which Plextor very kindly sent me for review. In fact I’ll be looking at the 256GB version of the M6e M.2.. Also available are 128GB and 512GB versions.
So let’s find out how this new SSD performs in our range of tests.
Plextor company information
Plextor should need no introduction, but those of you who would like to find out more about Plextor, can do so at their website.
The Plextor M6e M.2. 256GB SSD
Now it’s time to take a look at the drive itself and what it came shipped with.
Plextor M6e M.2. Pro SSD package
The M.2. SSD I received was already mounted on a PCIe adapter. The M6e M.2. was removed from the bracket for most of the tests.
Now let’s head to the next page, where we look in more detail at the Plextor M6e M.2. 256GB SSD…..