M.2 SSD
An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification written for internally mounted storage expansion cards of a small form factor. The specification, originally known as the Next-Generation Form Factor (NGFF), is pronounced M-dot-2M.2 SSDs are designed to enable high-performance storage in thin, power-constrained devices, such as ultrabook and tablet computers. They are generally smaller than mSATA SSDs, for which they are intended as an alternative.
The M.2 form-factor specification was defined by the PCI Special Interest Group (PCI-SIG) consortium of technology industry vendors and the Serial ATA International Organization. The M.2 specification supports applications such as Wi-Fi, Universal Serial Bus (USB), PCI Express (PCIe) and Serial ATA (SATA
M.2 SSD vs. mSATA
M.2 is commonly referred to as an mSATA replacement, but mSATA SSDs still exist and will probably continue for some time in laptop platforms that support that form factor. Because M.2 and mSATA cards are different form factors and have different connectors, they cannot be plugged into the same devices.
PCIe support also allows M.2 cards to take advantage of the nonvolatile memory express (NVMe) protocol, which brings a large performance advantage over other types of interfaces due to reduced latency, increased IOPS and lower power consumption.
As of early 2017, the largest M.2 SSDs support 1 TB of capacity, more than any mSATA drives.
M.2 connectors support four lanes of PCIe bandwidth, or one SATA or USB lane.