What is an M.2 SSD?

In this blog post, we’ll take a super quick look at the new M.2 solid state drives (SSDs) and what they mean for you.

What’s M.2?

M.2 solid state drives are a relatively new type of solid state drive. ‘M.2’ is the name of the specification or standard which these new SSDs are made to. It dictates things such as the physical size, interface and connector options that manufacturers can use when making their products.

Think of it like a set of rules which manufactures must follow to ensure their device (e.g. an SSD) is compatible with someone else’s device (e.g. motherboard).

That all may sound a bit complicated, but basically, the easy way to quickly pick an M.2 SSD over a standard SSD is by the look of it.


What’s the point / Why do I want one?

  1. Speed! We’re talking ~2500MBps for M.2 SSDs vs ~500MBps for SATA SSDs.
  2. No cables. The cards plug directly into the motherboard which makes the case neater.
  3. Size. Tiny cards means smaller cases.

Most common SSDs you see are SATA SSDs which connect to the SATA bus on the motherboard via a SATA cable (makes sense right?).

The M.2 specification allows the manufacturer to directly hook into a choice of buses on the motherboard such as SATA, PCIe or USB without any cables.

Many new SATA SSDs are hitting the limits of the SATA bus. The PCIe bus can be MUCH faster than the SATA bus and many new M.2 SSDs are taking advantage of this.

Can I fit one in my PC? Where does it plug in?

Take a deep breath and read on.

M.2 devices are a little different to what most may be used to – they plug into a M.2 slot on the motherboard. I know, it’s confusing. We’ve just been talking about “PCIe” and “SATA” but that was about the BUS or channel the data is going over in the motherboard, not the actual connector you plug into.

So yes, M.2 devices have their own connector or slot on the motherboard. There’s actually a few variations of the slot to look out for in terms of physical size and where the little notch or cutout is in the connector.

  • The location (or locations) of the notch is identified with a single letter known as the key ID.
  • The physical size can vary in width and length and is usually specified as a 4 digit number representing width then length. For example, 2280 means 22mm wide X 80mm long.

If you’re reading this article, the main takeaway you should remember is this: MOST M.2 SSDs which use the PCIe bus (The fast ones) have a single notch on the “M” key and have a 2280 form factor (size). In the near future these may shrink down in size so make sure you check the sizes before purchasing. 

The older M.2 SSDs which use the SATA bus (the slower ones) commonly have two notches, on the B and M keys. These are often 2280 or 2242 in size.

Check out the full details of the notches and sizes on Wikipedia: https://en.wikipedia.org/wiki/M.2#Form_factors_and_keying

Examples / Recommendations

If you’re looking to buy a M.2 SSD, make sure your motherboard can support the SSD first! This means you’ll need a M.2 connector on your motherboard that will match your M.2 SSD, so you can plug it in.


We really like the Asus z170 Pro Gaming motherboard. It supports M.2 SSDs at PCIe 4x and a length of 42mm, 60mm, 80mm or 110mm. You’ll notice the M.2 connector towards the bottom right of the image.

The Asus z170 Pro Gaming Motherboard supports M.2 so is a great pick if you’re keen to test out some of the latest M.2 devices.

1 x M.2 Socket 3, with M Key, type 2242/2260/2280/22110 storage devices support (both SATA & PCIE mode)*1

As for the SSD, take a look at the Samsung 950 pro 512GB. It’s a “M” notched 2280 form factor SSD meaning it’ll fit perfectly in the above ASUS 170 Pro Gaming motherboard.

M.2 SSD ‘s look quite different to your traditional SATA SSD, with a much smaller form factor (physical size)

If you’ve installed an M.2 SSD in your system we’d love to hear about your experiences in the comments below!


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