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. Still, they 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.
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 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, USB (Universal Serial Bus), 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:
The “22” stands for the width of the M.2 and the second number for the length in millimeters. A 2280 M.2 is therefore 22 millimeters 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 to see what 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 is not really faster than standard 2.5-inch SSDs. They 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, while 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’s a swamp that needs to be navigated carefully. You have to know exactly what your mainboard can and cannot do about 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 how 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 your mainboard’s PCIe interface 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 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. Because of 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.
Modern M.2 NVME SSDs often have a heat sink on the top
Also, the NVMe protocol was developed to limit 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 your PC components, 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, we would like to explain exactly where the differences between all the different SSD types lie in the following sections. 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.
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 over this connection. For comparison: A SATA drive with 7200 rpm can reach 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.
Most don’t know 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. On the other hand, M.2 SATA SSDs offer the same performance as their 2.5-inch counterparts and are connected directly to the motherboard to require no cables.
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. Also, an mSATA SSD has a bare circuit board and is not protected by 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 has largely been replaced by the M.2 form factor and is no longer relevant today.
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) 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 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 PCI-E slot’s speed.
Due to the high price and the lower performance, this 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. The M.2 drive is essentially 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 – an option if you don’t have a suitable port
Some motherboard manufacturers will provide you with an empty M.2 carrier card for high-end models in the packaging in some unique cases.
Some M.2 SSDs can get very warm after prolonged use. If the M.2 module is mounted on a vertical card, 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.
We have summarized the loading times for you (in seconds):
The poor HDDs. That just had to be said. But back to the subject.
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 this 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, an 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:
Here we have to state that NVME-based SSDs have no advantage clearly. The frames here often fluctuate, and the numbers are mostly 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.
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.
Incidentally, if you still fluctuate between HDD and SSD even after the above loading times, please read our detailed article about it:
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 boring technical details.
Keys are the notches in the connectors of M.2 modules, which can 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 us gamers. Nevertheless, in the following table (based on the one from Arstechnica ), you will find the names of the most important keys and their intended use:
|KEY DESIGNATION||INTERFACES||COMMON USE FOR|
|A.||PCIe x2, USB 2.0, I2C, DisplayPort x4||Wi-Fi / Bluetooth, cellular cards|
|B.||PCIe x2, SATA, USB 2.0, USB 3.0, audio, PCM, IUM, SSIC, I2C||SATA and PCIe x2 SSDs|
|E.||PCIe x2, USB 2.0, I2C, SDIO, UART, PCM||Wi-Fi / Bluetooth, cellular cards|
|M.||PCIe x4, SATA||PCIe x4 SSDs|
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: 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 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. The B-Key-M.2 has six pins wide; the M versions have a five-pin connector.
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 current mainboards also support it. Also, 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?
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.