Non-Volatile Memory Express (NVMe) is the latest industry-standard software interface for PCIe SSDs. Formally it is an optimized “scalable host controller interface designed to address the needs of Data Center, Enterprise, and Client systems that utilize PCI Express (PCIe) based Solid-State drives.” NVMe is a layer between the device driver and the PCIe device, standardizing the rules with emphasis on scalability, low latency, and security.
The standard developed to allow modern SSDs to operate at speeds flash memory is capable of, a sharp advantage with faster read-write. The NVMe SSD enables the flash memory to run directly through the PCI Express (PCIe) serial bus interface as it offers high bandwidth due to being directly attached to the CPU rather than function through the limiting SATA speeds. As SSDs superseded the slower HHDs as primary storage, a fast interface was required to achieve optimal use of the quicker speed capabilities.
In other words, it’s a technological depiction of the bus, the memory component (SSD) uses to communicate with the computer, and not exactly a new type of memory. A communications interface and driver that outlines a command set and feature set of PCIe based SSD. It comes in two form factor, M.2 or PCIe expansion card, a 2.5-inch U.2 connector, but with both form factors, it directly connects electrically to the motherboard via the PCIe rather than SATA connection.
The NVMe supports up to 64K commands per queue, but the protocol requires only thirteen commands to deliver high performance. The interface is designed for high scalability and NVM independence to enable next-generation technologies to deliver 4KB I/O in a mere 10?s or less, which is about one-thousandth of the latency of a high power 7200 RPM SATA drive.
NVMe is an improvement over the last interfaces like Serial ATA (SATA), and Serial Attached SCSI (SAS), which were developed for the shabby Hard Disk Drives (HDDs) and were being used till now even when replaced with SSDs because the memory technology was rapidly evolving. Still, the communication interface was not given proper attention. HDDs are still used as they provide large capacity and cheap storage, while the flash memory has previously been only employed in mobile devices like tablets, smartphones, but now are more quickly coming to the primary computer market because of blazing fast speeds and comparatively cheaper than before.
Though disk benchmarks are not indeed an accurate indicator of memory performance, they offer a baseline of what’s probable with a particular drive and system. You can see a clear difference in performance when you use NVMe, with a read/write throughput far higher than the hard drives and slower SATA SSDs also lagging somewhat behind. As prices continue to drop for the latest NVMe SSDs, they are becoming commonplace for normal personal computer users.
NVMe permits drives to use PCI Express connection, which brings many advantages over the SATA SSD interface, feasible for many application and usage scenarios. NVMe doesn’t need the intervening HBA and can connect to a higher number of PCIe lanes. A SAS lane runs at 12GB per second, which contracts to just about 1GB per second after overheads. As well a SATA lane props half of that, while PCIe lane runs at 1GB per second, and a standard NVMe SSD can be attached to four such lanes, supporting up to 4GB per second. So, a SATA SSD runs at 0.5GB per second and an NVMe SSD at around 3GB per second, which is six times higher throughput.
Speed
NVMe is not affected by the ATA interface constrictions as it sits right on the top of the PCI Express directly connected to the CPU. That results in 4 times faster Input/Output Operations Per Second (IOPs) rivaling the fastest SAS option out there. The seek time for data is ten times faster. NVMe can deliver sustained read-write speed of 2000MB per second, way faster than the SATA SSD III, which limits at 600MB per second. Here the bottleneck is NAND technology, which is rapidly advancing, which means we’ll likely see higher speeds soon with NVMe.
Performance
NVMe enables drives to benefit from the same “pool” of lanes that directly connect to the CPU. That offers scalable performance by going beyond the conventional four lanes found in most PCIe SSDs and utilize them for added performance. PCIe sockets transfer more than 25 times more data than their SATA equivalent.
Power-efficient
NVMe drives consume a paltry amount of power in standby mode. Some of the NVMe companies have adopted the L1.2 low-power-consumption standby mode, meaning the power consumption will be under 2mW. A drastic 97 percent reduction from the 50mW used by an L1 state, widely used today. In addition to low power consumption in idle, there are other power states available for enterprise-grade users that can benefit from these to save power.
Compatibility
Regardless of form factor, NVMe directly communicates with the system CPU and works with all major operating systems.
Security
NVMe SSDs reinforce the industry-standard security solutions such as the Opal SSC and Enterprise SSC by the Trusted Computing Group, by supporting the security container commands akin to the security container commands found in the SCSI.
