M.2 SSD: types, definition, differences & performance

What is M.2 SSD

An M.2 SSD is no longer just a good thing for PC enthusiasts. Because M.2 SSDs are increasingly replacing the old hard drive and even SATA SSDs. Because everyone knows the form factors of 3.5 inches for HDDs as well as the common 2.5 inches for “normal” SSDs.

But while these are still the most common form factors and connection options, M.2 and NVMe SSDs are becoming increasingly popular in modern gaming PCs.

To be clear: M.2 and NVMe are not interchangeable terms, but they are closely related. Therefore, in this article, we will break down exactly what M.2 and NVMe actually are, what other types of SSDs there are, where they differ and how they can ultimately benefit your next PC.table of contents

The M.2 form factor explained

The M.2 form factor (formerly known as the next generation form factor or NGFF) is a more modern type of internally mounted expansion card that replaces the previous mSATA (mini-SATA) standard. 

In contrast to standard hard drives and SSDs.

M.2 storage devices are not connected to a mainboard via a cable but are inserted directly into the mainboard via a dedicated M.2 slot.

Depending on the type and functionality, an M.2 SSD can either use the standard SATA interface ( Serial Advanced Technology Attachment ) or the faster PCIe interface ( Peripheral Component Interconnect Express ). In both cases, however, it is connected directly to the mainboard. 

Since they are flush with the circuit board after connection (conventional hard drives or SSDs take up much more space here), M.2 SSDs enable a cleaner and clearer housing with less cable clutter.

Different SSD M2 disk drive isolated on white background
Different SSD M2 disk drives isolated on white background. 3d illustration

M.2 NVME and M.2 SATA SSDs look very similar

But the M.2 standard is not only limited to SSDs because certain peripheral devices such as WLAN cards can also be supplied in the M.2 form factor. 

However, the most common use for M.2 is for SSD data storage, which basically acts as an alternative to the existing 2.5-inch storage drives.

In particular, M.2 is an interface specification that supports multiple protocols and applications such as Wi-Fi, Universal Serial Bus (USB), PCIe (PCIe), and SATA. M.2-compatible products are also not limited to solid-state drives.

Also important in connection with M.2 SSDs are the different lengths in which the small sticks are sold. The following dimensions are the common production sizes:

  • 2242
  • 2260
  • 2280

The “22” stands for the width of the M.2 and the second number for the length in millimetres. A 2280 M.2 is therefore 22 millimetres wide and 80mm long. Although there are also lengths of 32 and 110mm, these are rarely produced or are practically irrelevant. There is currently only one width for the M.2 form factor.

Accordingly, you should always look carefully at which length your M.2 port supports. A 2242 model is of course compatible with a 2260 slot. Especially with small PCs or laptops, there is sometimes no space for the largest M.2 variants. Longer drives also have more space for more NAND flash chips.


It is important to note that M.2 SSDs that use the SATA interface are not really faster than standard 2.5-inch SSDs. They just take up less space and are easier to install. If you want faster speeds you have to make sure that your M.2 drive uses the NVMe interface protocol and that your mainboard has a suitable slot for it.

A few more words about M.2 compatibility of mainboards.

Desktop motherboards are more complicated in that some support both SATA and PCI Express data transfer on a given M.2 slot. 

For boards with two M.2 slots, support can vary between the two: some only support SATA, others only support PCI Express. And in the case of PCI Express M.2, an older motherboard may not support PCI Express x4, but the only x2!

In short, it is a swamp that needs to be navigated carefully. You need to know exactly what your mainboard can and cannot do with M.2 SSDs.

What is the NVME Protocol?

Now that we know that M.2 is a form factor, we still have to clarify what exactly is behind the NVME interface protocol.

NVMe stands for Non-Volatile Memory Express and relates to the way data is transferred rather than the shape of the product. NVMe is the latest powerful and optimized protocol to replace AHCI and complement PCIe technology.

The main difference to the existing SATA standard is that the PCIe interface of your mainboard. and is used to achieve significantly faster data transfer speeds than is possible with SATA.

 Depending on the manufacturer, you can see speeds with NVME SSDs that are five to six times faster than with a SATA-based model.

There is some NVMe storage that fits into a PCIe slot on your motherboard, much like a graphics card, but most models use the M.2 form factor. Due to their higher speed, NVMe-based SSDs typically cost more than 2.5-inch variants. Almost comparable to SSDs, which cost more than mechanical hard drives with the same storage space.

What is the NVME Protocol?

Modern M.2 NVME SSDs often have a heat sink on the top

In addition, the NVMe protocol was developed to limit the speed of modern SSDs only through their own flash memory and less through the SATA interface. 

Essentially, flash storage allows flash storage to work as an SSD directly over the PCIe interface instead of going over SATA and being limited by the slower SATA speeds.

Are all M.2 SSDs NVMe?

No. Remember, M.2 is just the form factor. M.2 SSDs can therefore come in SATA versions and NVMe versions. SATA M.2 SSDs and 2.5-inch SATA SSDs actually work with practically identical specifications. NVMe M.2, on the other hand, definitely not, as we explained above.

If you want to use an M.2 SSD when selecting components for your PC, it is important to consider whether you are getting a SATA-based or an NVMe-based model. Because your mainboard may not have the corresponding M.2 slots for both types (not every model allows PCIe data transfers). And even if this is the case, you shouldn’t waste money on a more expensive NVMe drive if your mainboard can only access data via the SATA protocol. Always check this carefully beforehand for compatibility.

SSD types: which ones are there?

For the sake of completeness, in the following sections, we would like to explain exactly where the differences between all the different SSD types lie. To remove the confusion about the names once and for all.


The best-known and currently cheapest form factor is the 2.5-inch SSD. The drive itself is enclosed in a lightweight case and requires SATA connections for power and data transfer. 

You can often find these drives in desktops, small form factor PCs, and laptops that are used as boot drives or even as the sole storage solution due to the ever-improving price-per-gigabyte ratio.

SSD types

2.5 inch SATA SSDs are still very common

Modern mainboards use SATA III with a maximum throughput of 600 MB / s (or 300 MB / s for the older SATA II). Most SSDs offer read/write speeds in the range of 530/500 MB / s via this connection.

For comparison: A SATA drive with 7200 rpm comes to around 100 MB / s, depending on its age, condition and degree of fragmentation. NVMe Drives, on the other hand, offer to write speeds of up to 3500 MB / s, which is largely due to the AHCI transfer protocol used by SATA SSDs.

What most don’t know is that M.2 SSDs and SATA SSDs are two completely different types of SSDs. M.2, as described above, is a form factor and SATA is a transmission technology.

SATA SSDs come in both 2.5-inch and M.2 form factors, but the 2.5-inch form factor is what most people associate with an SSD. SATA SSDs come with two cables (data and power) and are mounted in the housing. 

M.2 SATA SSDs, on the other hand, offer exactly the same performance as their 2.5-inch counterparts and are connected directly to the mainboard, so that no cables are required.

  • Also interesting for you: Our current SSD test


Not to be confused with an M.2 SSD.

mSATA defines both a form factor and an interface for compact SSDs. An mSATA SSD can be used as a boot drive (in an older, compact laptop or tablet) or as an SSD cache to speed up the operation of a mechanical hard drive. However, it is a type of SSD that is slowly becoming extinct.


Compared to SATA SSDs, mSATA SSDs are roughly one eighth the size but offer the same speed. This makes them ideal for netbooks, laptops or tablets that lack space in the housing. In addition, an mSATA SSD has a bare circuit board and is not protected by a housing like a 2.5-inch SSD.

A few years ago, a subset of desktop motherboards included mSATA slots to enable onboard installation of an mSATA SSD for caching. However, MSATA was largely superseded by the M.2 form factor and is no longer relevant today.

M.2 SSDs

M.2 SSDs look similar to mSATA models, but that’s pretty much the only thing they have in common. We have already clarified the most important criteria for an M.2 SSD above. So here are just a few more important facts:

  • M.2 is a form factor for SSDs (solid state drives) that is shaped like a RAM bar.
  • These SSDs are generally faster, but more expensive than traditional 2.5-inch SSDs.
  • Thin laptops are increasingly using M.2 SSDs because they take up less space.
  • M.2 SSDs (currently) have a storage size of up to 2 TB. Other form factors offer more capacity.
  • To use an M.2 SSD in your desktop PC or laptop, you need a motherboard with M.2 slots. Some have two or more M.2 slots so that you can operate your SSDs in RAID.
  • While 2.5-inch SSDs use the SATA bus, M.2 SSDs can be operated via SATA and PCIe.
M.2 SSDs

M.2 SSDs are available in different lengths

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 and guarantees better performance for tasks such as file transfer, video or photo editing, transcoding, compression and decompression.


There are now even PCI Express SSDs for the consumer market. This form of SSD is the most expensive in terms of price per gigabyte and offers less performance than NVME M.2 SSDs. These SSDs use the PCI-E slot as an interface and are therefore limited to the speed of the PCI-E slot. 

Due to the high price and the lower performance, this of course only makes sense if the older mainboard of your desktop PC does not have an M.2 slot, but you still want to install a PCI Express / NVMe SSD.

The M.2 drive is used as a “carrier card” by a PCI expansion card. Essentially, the M.2 drive is mounted on a PCI Express expansion card with an M.2 slot on board and plugged into a normal PCI Express slot with at least four PCI lanes.


The M.2 SSD on a PCIe card – if you don’t have a suitable port, it’s an option

In some unique cases, some motherboard manufacturers will provide you with an empty M.2 carrier card for high-end models in the packaging.

Some M.2 SSDs can get very warm after prolonged use. If the M.2 module is mounted on a vertical card, as here, it can mean better ventilation and, in theory, less or no throttling due to heat.

M.2 (NVME) SSD vs. SATA SSD: What is more for gaming?

As gamers, we are of course still interested in the burning question. Does an NVME M.2 SSD have an advantage over a SATA SSD in gaming? 

First, let’s take a look at the loading times.

loading time

M.2 (NVME) SSD vs. SATA SSD: What is more for gaming?

We have summarized the loading times from the video in a table for you (in seconds):

Star Wars Jedi17.3317.6627.89
Shadow of the Tomb Raider7.8613.7332.63
microsoft flight simulator21.624.8635.56
Battlefield 515.151623.2
AC: Odyssey19.628.623.2

The poor HDDs. That just had to be said. But back to the topic.

You can see quite quickly that an NVME SSD is the fastest, but the differences to a normal SATA SSD are barely noticeable in some games. Nevertheless, you will get the shortest loading times and with some games that can be just under 10 seconds ( up to 50% faster loading times ). So if you really don’t feel like waiting, you can access this without hesitation.

So for the loading times in games, and NVME M.2 SSD definitely brings something.  

However, it is also worth mentioning that the increase in speed provided by the NVMe protocol mainly applies to sequential read and write processes of data and not to random read and write processes.

Therefore, outside of gaming, you will only notice a noticeable increase in speed if you use your computer for certain more demanding tasks such as editing 4K video material or regularly transferring large amounts of data from one drive to another. 

FPS in games

Next, let’s take another look at the FPS in games:

FPS in games

Here we have to clearly state that NVME-based SSDs have no advantage. The frames here often fluctuate and most of the time the numbers are identical, but at no time do you see a stark difference.

 Of course, depending on the game scene, you might have 3-5 more FPS with an NVME M.2, but sometimes the SATA SSD is also ahead.

Although you only see data for GTA 5, this video shows the same result in Call of Duty Warzone.

Ergo: You won’t really have an FPS advantage with an M.2 NVME SSD and that shouldn’t be your incentive to buy. However, you will definitely see an improvement for faster load and boot times.

By the way, if you still fluctuate between HDD and SSD even after the above loading times, please read our detailed article about it:

  • SSD vs. HDD in gaming – there are all the facts on the subject

What do M.2 keys mean?

In order to really explain everything about the M.2 SSD to you, we don’t want to leave out the somewhat more boring technical details.

Keys are the notches in the connectors of M.2 modules, which can be used to differentiate between the types of M.2 products. 

First of all: M.2 SSDs with key M or key B are really relevant for the consumer market and for us gamers.

Nevertheless, in the following table (based on that of Arstechnica ) you will find the names of the most important keys, as well as their intended use:

A.PCIe x2, USB 2.0, I2C, DisplayPort x4Wi-Fi / Bluetooth, cellular cards
B.PCIe x2, SATA, USB 2.0, USB 3.0, audio, PCM, IUM, SSIC, I2CSATA and PCIe x2 SSDs
E.PCIe x2, USB 2.0, I2C, SDIO, UART, PCMWi-Fi / Bluetooth, cellular cards

M.2 SSD modules are plugged into printed circuit boards using mating connectors or cutouts on both sides. 

In contrast to mSATA, M.2 SSDs have two types of connections, which are also known as sockets, sockets or sockets: B-socket and M-socket.

A single M.2 plug-in card can also have both types of keys. The key type determines the number of PCIe lanes that are supported and ensures that only compatible M.2 SSDs fit into a port. 

An M.2 with a B-Key supports one or two PCIe lanes, and an M.2 with an M-Key supports up to four. In addition, the B-Key-M.2 have a connector that is six pins wide; the M versions have a connector that is five pins wide.

Accordingly, it is important to check whether your mainboard provides the appropriate M.2 port. However, for us gamers, only the M.2 Key M is relevant.

especially since most modern models have this and it is also supported by current mainboards. In addition, there are only very few M.2 models with key B, this is only relevant for external hard drive cases.

Which are the best M.2 SSDs?

Exactly on this topic, we already have detailed purchase advice with selected M.2 SSDs. Check it out:

  • Best M.2 SSD in the test

In short, NVME-based models are the fastest and best on the market today. If you want to spend the money, you will get a lot of speed on your computer.

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