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SSD M.2 Standards and Performance
The M.2 connector has been created not only for SSD carriers, but also for Wi-Fi cards, Bluetooth, NFC modules and GPS. M.2 allows you to implement various devices, and thus different interfaces.
Disks with two interfaces are available within M.2 SSDs:
- using the SATA III standard;
- using the PCIe standard (PCI Express).
M.2 drives with SATA III interface do not differ in performance from typical 2.5-inch media. It's the same disks, only in a different format. SATA III carriers use the AHCI protocol for operation, which strongly limits SSD storage media - the maximum transfer of SATA III interface is 600 MB/s.
M.2 drives that use the PCIe interface (PCI Express) are much faster carriers. In this case, the NVMe protocol, designed specifically for SSD drives, is responsible for the operation. It allows you to use the bandwidth of the PCI Express standard for the fastest possible file transfer. However, performance will depend on the generation of the PCIe interface and the number of communication lines. Currently, disks using the PCIe 3.0 x4 interface (four lines) achieve transfers of 4000 MB/s! However, the cheaper M.2 drives with PCIe 3.0 x2 (two lines) are limited to 1969 MB/s. It does not mean, however, that each disk in a given standard will be just as fast - the results depend on the used memory and controllers. However, even the basic M.2 drive from NVMe will be much more efficient than SATA III carriers.
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