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The M.2 Form Factor with PCIe® or SATA Interfaces

Recently, additions to the available form factors and interfaces of storage drives have brought more options for computer users. A pair of changes can be confusing to some users, however. This article explains more about what the M.2 form factor is and how it interacts with various interfaces.

M.2 form factor

M.2 is a form factor specification, designed to replace the mSATA standard. The specification spells out the physical size and shape of the card. The card itself can be used for different applications, but the application this article talks about is solid state drives.

The M.2 form factor has been designed to maximize PCB (printed circuit board) space while minimizing the footprint of the M.2 module itself. The module is rectangular, with possible widths of 12, 16, 22, or 30 millimeters. Generally, solid state drives are 22 millimeters wide. Lengths can also vary; 16, 26, 30, 38, 42, 60, 80 or 110 millimeters. Most motherboards will accommodate a variety of lengths for an M.2 module, the width is more fixed on motherboards as the connector is placed on the edge of the short side of the M.2 card.


M.2 SSD in a laptop

PCIe and SATA interfaces

M.2 is the form factor of a particular SSD. There is also a physical interface that connects the drive to the rest of the computer. Although there are a fair number of different interfaces, we're going to look at PCIe and SATA.

SATA interface

The SATA, or Serial ATA, interface is older than PCIe, but when it was first developed, it brought important advances to computing, such as hot swapping abilities. SATA for storage drives was developed for hard drives, when solid state drives came on the market, they adopted the same interface so users could easily upgrade their storage drive.

PCIe interface

The PCIe, or Peripheral Component Interconnect Express, interface is a newer interface that features a smaller physical footprint. The real advantage of the PCIe interface however, is the ability to transmit data on up to four lanes. When combined with the logical interface NVMe®, read/write speeds increase for SSDs compared to using SATA and the AHCI logical interface.

SSD with PCIe interface

Which interface should I get?

The most important aspect of which interface is right for you is which one will work in your computer. It can be difficult to tell the difference between a PCIe and a SATA connection if you look at the slot on the motherboard. Check your computer specifications to see which interface your computer supports. You can also use the Crucial® Advisor™ tool or System Scanner tool to find a compatible part.

If you have the option of multiple M.2 slots where at least one supports PCIe, choose that slot for an SSD upgrade. PCIe, when combined with NVMe, will result in faster read and write times.

©2019 Micron Technology, Inc. All rights reserved. Information, products, and/or specifications are subject to change without notice. Neither Crucial nor Micron Technology, Inc. is responsible for omissions or errors in typography or photography. Micron, the Micron logo, Crucial, and the Crucial logo are trademarks or registered trademarks of Micron Technology, Inc. . PCIe are registered trademarks  of PCI-SIG. NVMe is a registered trademark of NVM Express, Inc.  All other trademarks and service marks are the property of their respective owners.