M.2 is a form factor specification designed to replace the mSATA. The specification indicates the physical size and shape of the card. The card itself can be used for several applications.
The M.2 form factor was designed to maximize the PCB (printed circuit) area while reducing the footprint of the M.2 module itself. The module is rectangular with a possible width of 12 16 22 or 30 millimeters.
Usually, solid-state drives are 22 millimeters wide. Most motherboards will fit a variety of lengths for the M.2 module. The width is more fixed on the motherboards because the connector is located on the short side edge of the M.2 card.
What is NVMe?
The NVMe Host Memory Interface Specification NVMe Express or Non-Volatile is a communication protocol specifically designed for working with flash memory using a PCIe® bus (PCI Express®). It was created to take advantage of the nature of solid-state drives.
Combined with the PCIe bus and the increased read and write speeds of NAND technology, the NVMe form factor protocol creates faster non-volatile storage. Learn more about PCIe here.
NVM Express Inc. Is a consortium in the computing industry created to oversee the development of standards around this scalable host controller interface.
The combination of NVMe m2 form factor protocol and PCIe connection with SSD results in four times faster read and write speed than SATA SSD with SCSI protocol.
NVMe form factor complements the appropriate structure for contemporary processor platforms and applications. A parallel structure allows additional commands to flow simultaneously.
NVMe uses an optimal path for commands and completing I/O and supports operation with up to 64000 commands within a single I/O queue and 64000 possible queues. Older protocols are serial in nature with a limited number of commands in the single queue.
Because NVMe is specifically designed for NAND technology used in solid-state drives, it takes advantage of the way basic technology works to create a faster drive.
What is PCIe?
PCIe also known as PCI Express® or Interconnect Express Interconnect Component is a high-speed bus used for computers. It is a physical connection that transfers information and data from one device to another inside the computer or between the computer and peripherals.
The specifications for the PCIe interface are maintained by the PCI Special Interest Group, a consortium of more than 900 companies working to create a common standard.
Implementing multiple PCIe lanes is one of the most important features of the standard. A path is a single serial data connection similar to a SATA connection. PCIe uses four paths for storage devices resulting in four times faster data exchange than a SATA connection.
The PCIe m.2 form factor or Interconnect Component Interconnect Express interface is a newer interface that includes a smaller physical footprint.
The real advantage of the PCIe interface is the ability to transfer data up to four paths. Combined with the NVMe m2 form factor logical interface, the read / write speed for SSD increases compared to the use of SATA and the AHCI logical interface.