WHAT IS NVMe
NVMe(i.e. non-volatile memory express) is a storage protocol that defines a command set and feature set for PCIe-based solid-state drives (SSDs) .
NVMe created to accelerate the transfer of data between enterprise and client systems and SSDs over a computer high-speed PCIe (Peripheral Component Interconnect Express) bus.
NVMe is a new standard
Older standard by name AHCI (Advanced Host Controller Interface) was designed for hard drives. Since the introduction of non-volatile storage (e.g. NAND and MRAM), the industry must have developed a software interface that abolishes the limits of AHCI.
The main benefits of NVMe-based PCIe SSDs over SAS-based and SATA-based SSDs are, reduced latency in the host software stack, higher input/output operations per second (IOPS), and potentially lower power consumption, depending on the form factor and the number of PCIe lanes in use.
NVMe can support SSDs that use different types of non-volatile memory, including NAND flash and the 3D XPoint technology developed by Intel and Micron Technology. Supported form factors include add-in PCIe cards, M.2 SSDs and U.2 2.5-inch SSDs. NVMe reference drivers are available for a variety of operating systems, including Windows and Linux.
Differences between BUSs in data transfer
Using 16 lanes, PCIe Gen4 can transfer data at speeds up to 32,000 MB/s.
Differences between storage protocols