What Is an M.2 SSD? A Basic Definition

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M.2 SSDs are faster but more expensive than 2.5-inch ones.

M.2 is a form factor for SSDs (solid-state drives) (opens in new tab) that’s shaped like a stick of gum. These SSDs are generally faster but more expensive than traditional, 2.5-inch SSDs. 

Thin gaming laptops  (opens in new tab)are increasingly using M.2 SSDs because they take up less room than 2.5-inch SSDs or hard drives. 

M.2 SSDs go up to 2TB in storage size. Other form factors (opens in new tab) offer more capacity.

In order to use an M.2 SSD in your gaming PC (opens in new tab) or laptop, you’ll need a motherboard (opens in new tab) with M.2 slots. Some motherboards (opens in new tab) have two or more M.2 slots, allows you to run your SSDs in RAID.

While 2.5-inch SSDs use the SATA bus (opens in new tab), which debuted in 2000 and was originally geared toward hard drives, and add-in cards use the PCIe (opens in new tab)bus, which is faster and has more bandwidth than SATA, M.2 SSDs can go either way, depending on the product. Additionally, some of the fastest and best SSDs (opens in new tab) use the NVMe interface, which was made for rapid storage devices. 

So an M.2 SSD can be SATA-based, PCIe-based with NVMe support, or PCIe-based without NVMe support. An M.2 SSD with NVMe support offers up to five times more bandwidth than SATA M.2 models, bringing better performance in key tasks, such as file transfers, video or photo editing, transcoding, compression and decompression.

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) 

This article is part of the Tom's Hardware Glossary (opens in new tab).

Further reading:

Scharon Harding
Scharon Harding

Scharon Harding has a special affinity for gaming peripherals (especially monitors), laptops and virtual reality. Previously, she covered business technology, including hardware, software, cyber security, cloud and other IT happenings, at Channelnomics, with bylines at CRN UK.
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SSD
4 Comments Comment from the forums
  • Starkman
    Nice, thanks!
    Reply
  • JohnTheSock101
    You can get an 8tb m.2 off of Newegg for $1,300 so no, the limit is not 2tb
    Reply
  • geofelt
    m.2 is a size format.
    m.2 is not inherently faster as the lead in statement indicated.
    m.2 can come in both sata and pcie versions with the pcie versions showing some 5-10x better sequential speeds in synthetic benchmarks.
    As a practical matter, all ssd devices will perform similarly in random I/O which is what windows does most. A huge benefit compared to a HDD.
    It is the sequential benchmark performance that is better with the pcie versions.
    And, even that speed has it's limits.
    As I recall, game loading benchmarks differed by perhaps 2 seconds.
    Reply
  • USAFRet
    JohnTheSock101 said:
    You can get an 8tb m.2 off of Newegg for $1,300 so no, the limit is not 2tb
    Greater than 2TB is only a recent thing.

    https://www.tomshardware.com/reviews/sabrent-rocket-q-nvme-ssd(June 2020)

    "Up until recently, your only option to go beyond 2TB was to get a 2.5” SATA SSD, like the Samsung 860 series or WD Blue 3D, but those drives are limited to about 4TB and are slower than NVMe SSDs. "
    Reply