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How to Choose the M.2 Expansion Slot Interface?

Improve System Performance with the Optimal Cost Structure The Two Best Choices for SSD Interface Standards - M.2 and NVMe Gen4

For general and industrial computers, you need to look at the specification sheet to see the words “M.2” in the memory interface field. What do these words mean? What is their purpose in industrial control?


M.2 is an expansion interface standard for computer motherboards. M.2 was created by the two major organizations of PCI-SIG and SATA-IO. Originally named Next Generation Form Factor (NGFF), it was changed to M.2 in 2013. However, some industry experts still refer to the technology as NGFF.


Currently, industrial computers are used in a range of diverse applications. Often used in Wi-Fi, Bluetooth, NFC, and SSD expansion cards, M.2 devices allow systems to be equipped with wireless communications, expanded data storage capacity and increased read speeds. The dimensions of the miniature M.2 are suitable for various expansion card types. If motherboards are entirely customized, it will result in higher costs and longer development times. By reserving M.2 slots, the functions can be adjusted according to the application needs, improving the flexibility of motherboards and shortening development time.


Before M.2, the most common transmission standard for SSD was mSATA. However, the dimensions of mSATA are fixed. With the increasing demand for SSD storage on the market, if mSATA continues to be used, SSD capacity can only be increased without changing the size of the drive. That would significantly increase the cost per unit of storage. In contrast, M.2 offers different interface sizes. Currently, the exterior dimensions of the SSD are 22 mm in width, and the length depends on the amount of internal flash memory, which could be 30 mm, 42 mm, 60 mm, 80 mm, or 110 mm. M.2 offers slots for the dimensions mentioned above. When designing industrial computer motherboards, M.2 slot types can be selected according to the application needs. Generally, for handheld devices or industrial computers installed in smaller areas, the 22 mm x 30 mm or 42 mm specifications are chosen because of the limited space and more minor storage needs. If the space allows and requires greater data storage the system could use 22 mm x 60 mm, 80 mm, or 110 mm M.2 specifications.


With the two significant advantages described above, the M.2 standard has gradually become the mainstream standard for SSD. In addition to maximizing performance by using a suitable size, another benefit of M.2 is its plug-and-play characteristic for transmitting data. It does not require additional data transmission and power cables, which greatly simplify motherboard designs. Therefore, out of all technologies, SSD is the biggest adapter of M.2 standards. As for transmission speed, M.2 offers 600MB/s, which is the same as mSATA and SATA 3.0, allowing it to satisfy most application requirements.


Apart from M.2, another critical transmission technology for SSD is NVMe (Non-Volatile Memory Protocol). NVMe is a standard explicitly designed for SSD. Compared to the AHCI standard for traditional mechanical hard drives, NVMe offers more command queues and more commands transmitted per queue and requires fewer CPU cycles and shorter latency to transmit commands. NVMe SSD, which uses PCIe for data transmission, offers superior bandwidth and response speed performance. In recent years, PCIe has transitioned from Gen3 to Gen4. With double the transmission speed, SSD supports more demanding applications and operating loads and offers better flexibility and bandwidth. Together with better energy-saving performance, it is applicable for systems with large amounts of data.


According to market conditions, M.2 has become a standard specification among industrial computers. PCI NVMe SSD Gen4 is rising and will become the next mainstream standard for SSDs. Many of DFI’s products already have built-in M.2 technologies, and we are actively deploying PCI NVMe SSD Gen4. Several of DFI’s products already have this standard built-in. Our R&D and sales teams are also providing professional advice to customers. Contact us for more information.


You can also visit our website to learn more about the motherboard products that support M.2: https://www.dfi.com/category/index/1