Storage comes in a lot of shapes and sizes but this time around it evolved into something much bigger. The Solid State Drive or SSD is a lot more common and will eventually replace the traditional mechanical Hard Disk Drive (HDD) in the near future. Moreover, high performance SSDs are still using the SATA Interface with AHCI Controller which is the same as the mechanical hard drive tech because of IEEE Standardization.
Meanwhile there are high-end SSDs that are designed to take advantage of high speed or high bandwidth output of the PCI Express (PCI-e) interface with the use of AHCI controller interface integration specification. Manufacturers are now working for the NVMe controller interface specification to eliminate roadblocks to unleash the SSD’s true nature.
NVM Express (NVMe) or Non-Volatile Memory Express, is a standardized high performance host controller interface for PCIe SSDs that will ultimately deliver plug-and-play functionality for PCIe-connected SSDs on all platform.
The first NVMe prototype was seen back in 2007, where a NVMHCI working group led by Intel was formed that year to perform for research and development on the Non-Volatile Memory Host Controller Interface which aims to remove the bandwidth limitations of SATA and shedding the AHCI communication protocol. As the group finalized PCI Express as the standardized connection interface, version 1.0 of the specification was released on 2011, followed by version 1.2 update on 2014.
Advantages of NVMe: Low Latency
When an AHCI controller executes a command, an un-cacheable register read consumes 2000 CPU cycles and there are 4 un-cacheable register reads per command. This translates into 8000 CPU cycles, or roughly 2.5 µs of latency per command. NVMe on the other hand, will not experience such delay as it will directly communicate with the CPU, thus, skipping all the unnecessary communication that causes delay.
Advantages of NVMe: High Performance
Low latency isn’t the only advantage you’ll get from NVMe, as it also offers a much higher IOPS (Input/Output Operations Per Second). NVMe is capable of supporting up to 64K I/O queues, with each I/O queue supporting up to 64K commands, taking the full advantage of NAND Flash’s parallel read and write. AHCI on the other hand, support only single I/O queue with up to 32 commands per queue, which leads to a much slower performance compared to NVMe.
NVMe – The Mainstream Storage Interface Standard
With Intel 9 / 100 series chipset now supports NVMe and Operating System such as Windows 8.1 Windows Server 2012 R2 or later that comes with built-in NVMe driver, SSD manufacturers are seen releasing consumer grade NVMe SSD products starting from last year as well as during Computex Taipei back in the month of June. In August, Plextor set to announce the availability of its consumer grade M8Pe series NVMe SSD.
NVMe are bound to become the future standard of mainstream storage interface, as well as the advancement of NAND flash technology and it’s slowly manifests in various form of interfaces i.e M.2, PCIe, U.2,etc. As Market research institution predicted the possibilities of NVMe to replace AHCI as the new standard for mainstream SSD in 2017, and this marks the coming era of NVMe SSD.