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M.2 is a form factor for SSDs (solid-state drives) that’s shaped like a stick of gum. The M.2 form factor was formerly known as the Next Generation Form Factor, or NGFF. These SSDs are generally faster but more expensive than traditional, 2.5-inch SSDs. M.2 SSDs go up to 2TB in storage size. Other form factors offer more capacity.

M2 SSD examples
Most M.2 SSDs are 22 x 80mm (W x L), but can be shorter or longer. You can tell what size an M.2 SSD is by reading the four or five-digit number in its name or on its printed-circuit board (PCB). The first two numbers are its width, while the others are its length (example: M.2 Type-2280). Having a longer SSD means more space for NAND chips but not necessarily more storage space. Below are common M.2 SSD sizes:
  • M.2 Type-2280 (22 x 80mm)
  • M.2 Type-2230  (22 x 30mm)
  • M.2 Type-2242 (22 x 42mm)
  • M.2 Type-2260 (22 x 60mm )
  • M.2 Type-22110 (22 x 110mm)
M2 SSD keys

An M.2 SSD is “keyed” to prevent insertion of a card connector (male) to an incompatible socket (female) on the host. The M.2 specification identifies 12 key IDs on the module card and socket interface but M.2 SSDs typically use three common keys: B, M, and B+M. You will find the key type labelled on or near the edge connector (or gold fingers) of the SSD. Before deploying M.2 SSDs, determine the type of socket on the host and check the module connector keying, as each connector should be inserted only in the appropriate socket.

It’s important to note that M.2 SSDs which utilize the SATA interface aren’t really faster than standard 2.5” drives, they just take up less space and look cleaner. If you want faster speeds, you’ll have to make sure your M.2 drive is utilizing the NVMe interface protocol. These are more expensive.

NOTE: NVMe use a PCIe interface and cannot be used with Raspberry Pi’s. They are primarily intended for PC motherboards that are designed for the NVMe interface – not all currently are.

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