M.2 vs PCIe SSDs: What’s the Difference?

Deciding between ones like M.2 or PCIe is a monumental task in many regards. However, the good news is that there are some specific things you can look for to make a good choice.

Hello everyone! My name is Lavelle and I am a professional photographer, videographer, and filmmaker. As a graduate of computer engineering technology and after spending decades learning more and more about technology, I have experienced firsthand the challenges that come along with making sound technology choices.

In this article, I will explain exactly what is the difference between M.2 and PCIe. I will also cover the benefits and disadvantages of each drive. Additionally, I will look at a parallel comparison of the two drives and answer some frequently asked questions.

Key Takeaways

  • M.2s are quickly becoming the component of preference for computer designers.
  • PCIe SSDs are less expensive than most M.2 SSDs.
  • M.2s are a much more compact component than the PCIe, however, PCIe SSDs do typically store more data.

What is M.2 Drive?

The M.2 drive is a form factor and a connector. Unlike the PCIe that we will cover shortly, the M.2 drive is a type of expansion card that was developed to set a new standard. The components that make up the M.2 form factor are much smaller and because of that, the M.2 works great with smaller devices such as laptops and tablets. 

Technically speaking, the M.2 can be used with multiple sectors including wifi, Bluetooth connectivity, NFC, and other such devices. Its most common use, however, is with SSD (solid state drives).

M.2 Pros

Some of the advantages of the M.2 drive include its size and connection capabilities. The M.2 slot is native to most new motherboards and allows most computers to connect to multiple devices easily.

Another impressive thing about the M.2 connector is that it is compatible with PCIe ports that are 3.0 version or newer and it is also compatible with PCIe NVMe, SATA, and USB ports, all of which should be 3.0 or newer as well.

M.2 Cons

Primarily, the biggest drawback of the M.2 is its price point. For instance, the M.2 SSDs tend to be much more expensive than PCIe drives and it does not hold as much data as the PCIe.

What is PCIe Drive?

A PCIe drive is a series of connectors. The acronym PCIe stands for Peripheral Component Interconnect Express. The PCIe slot is used to connect high-speed components to motherboards. Most motherboards do have some version of PCIe connectors as a part of their design.

A standard PCIe port is used for data transfer and is known for its speed. The standard PCIe port transfers data approximately six times faster than SATA interfaces, and PCIe ports that are NVMe enabled can transfer data at an even higher rate.

PCIe Pros

One of the advantages of PCIe is that it is compatible with most graphic cards, most hard drives, most SSDs, wifi, and ethernet hardware. This compatibility range makes the PCIe drive a very attractive option for many computer designers.

PCIe Cons

The concern when it comes to the PCIe is its size. Since the M.2 is much more compact, many computer designers are now replacing the PCIe with the M.2. to save space. Therefore, the PCIe is somewhat in danger of becoming obsolete at some point down the road.

M.2 vs PCIe: Side-by-Side Comparison

Let’s look at a parallel comparison of the M.2 versus the PCIe.


The PCIe performs a sequential read of 6600 MB/s and a sequential write speed of 5000 MB/s compared to 3500 MB/s and 3300 MB/s for the M.2.


The M.2 can be configured to work with SATA, PCI-e, and PCI-e NVMe. In comparison, the PCIe interface is much more limited and is being replaced, in many cases, by the M.2.


As we look at compatibility, here’s the breakdown of the M.2 versus PCIe from a component compatibility perspective.

M.2 Components Compatibility:

  • Wi-Fi Cards
  • Bluetooth
  • Near Field Communication
  • Satellite Navigation
  • Digital Radio
  • Wireless WAN

PCI-e Components Compatibility:

  • Graphics Cards
  • Hard Drives
  • Solid State Drives
  • Wi-Fi
  • Ethernet Hardware


The one area where M.2s and PCIe’s overlap is in the SSD category. A side-by-side comparison in this area shows that an M.2 SSD such as the Adata XPG SSD, boasts read and write speeds of 7400 MB/s and 6800 MB/s respectively. 

Meanwhile, the PCIe Crucial P5 Plus lists its read and write speed at 6600 MB/s and 5000 MB/s. This is somewhat different from the norm, as one of the advantages of the PCIe is its speed in most cases.


When comparing the same two SSDs, the M.2s Adata XPG with 1TB of storage is priced at $59.99 while the PCIe Crucial P5 Plus with the same 1TB of storage space is priced at $53.99. Typically, the M.2 SSDs are more expensive than the PCIe SSDs.


Here are some questions related to the difference between M.2 and PCIe.

Can M.2 be Used in PCIe?

Yes, however, it does not fit into a PCIe slot directly. Instead, it must be inserted using an expansion card.

Is M.2 or PCIe Faster?

In general and all things equal, the PCIe is faster than the M.2. However, if the M.2 slot is using PCIe lanes, then it will be as fast as a PCIe M.2. Also, if the M.2 slot is running off SATA bandwidth then it will be noticeably slower than the PCIe.

What Is the Difference Between PCI and PCIe?

Technically they are the same. Most computers now have PCIe connectors which are an upgrade from the original PCI connectors. The PCIe replaced PCI, AGP, and PCI-X. 

Final Thoughts

In summary, PCIe is a family of connectors that have been used in almost every computer that you will find. The M.2 is a type of connector as well but it is also a form factor. The M.2 is typically small, compact, and slim while the PCIe is usually a larger component. 

In most cases, M.2 ports are used for M.2 NVMe SSDs while PCIe ports are normally used for a much wider range of components.

What’s your experience with M.2 and/or PCIe? Have you noticed any major differences? Share your thoughts in the comments below.

Until next time, enjoy the wonderful world of technology!

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