mSATA and M.2 SSDs: What’s the difference?

With the increase in motherboards and systems beyond portable devices supporting mini-SATA (mSATA) and M.2 standards for SSDs, we have seen ongoing confusion between these two standards.

In short, mSATA and M.2 SSDs are both high-performance storage devices, however, the most obvious difference between them is their compatibility.

In this article, we’ll give you an overview of both SSD types, their benefits and drawbacks, and how to decide which one is best for your upgrade.

An mSATA SSD is a solid state drive (SSD) that conforms to the mSATA interface specification developed by the Serial ATA (SATA) International Organization.

mSATA SSDs are small factor SSDs. In fact, Crucial’s mSATA SSDs are one-eighth the size of our standard 2.5-inch drives, and are designed to plug into an mSATA socket on a system’s motherboard. mSATA SSDs are generally designed for use with portable devices such as laptops, tablets and notebooks.

M.2 SSDs are the other type of small form factor SSDs and are around the size of a stick of gum. The M.2 form factor is designed to maximize your PC or laptop’s printed circuit board (PCB) while minimizing the amount of space it takes up. To connect an M.2 SSD, your motherboard will need to have an M.2 slot. Crucial M.2 SSDs are designed for space-constrained devices like tablets and ultrabooks.

For more information on different form factors, read our article on understanding M.2, SATA, PCIe and NVMe SSDs.

Both mSATA and M.2 SSDs are designed for small devices such as laptops, tablets and notebooks, but their main difference is compatibility.

SATA and PCIe interfaces are the types of physical connections that transmit data to and from the storage device and the rest of the computer. An M.2 SSD can support SATA or PCle interfaces, while an mSATA SSD can only support a SATA interface. 

The mSATA form factor is relatively straightforward in terms of compatibility. The only issue we've seen has been when users try to put them in a mini PCIe slot that’s not capable of supporting mSATA. While the slots looks identical, (and some motherboards support both), a PCIe-only slot/motherboard will not run any mSATA drives.

The most important thing to remember when dealing with these standards is that it's best to refer to your system documentation, or to use a resource like the Crucial® System Scanner, to check the SSD compatibility with your system. Some systems require PCIe-based devices, while others require SATA-based devices. Some can use both, but might need to be configured to one mode or another in your system's UEFI or BIOS. The standards are not interoperable, even though the pinouts and slots may be similar or identical. This is the most frequent issue we see regarding problems with installation of these drives, and it might require exchanging the drive for one with the correct compatibility.

M.2 drives, also known as Next Generation Form Factor (NGFF), feature multiple form factors based on the drive dimensions, layout of NAND components, and keying of the pins of the drive's connector. Crucial drives currently ship in a 2280 form factor (22mm by 80mm, either single-sided or dual-sided NAND layout), with B and M keying notches to maximize compatibility for SATA and M-keying only on our NVMe PCIe drives. Some M.2 slots have different keyings, such as A and E-keying. Crucial's current drives will not fit in these keyed slots, which are usually reserved for Wi-Fi and Bluetooth adapters. 

Using your hardware documentation or any other support resources, verify that your system will support a given drive before purchase. This can’t be stressed enough as it will save you time trying to diagnose and fix detection problems that are often caused by a simple difference in protocol between your socket and storage device. It will also ensure the easiest installation experience possible.