Connector m 2 for ssd drives. What types of SSDs are there? Consider PCI-Express, M.2, mSATA and SATA Express. Development of the SATA interface

16.05.2022

Both in the past and this year, articles about SSDs can be safely started with the same passage: “The market for solid-state drives is on the verge of serious changes.” For many months now, we have been looking forward to the moment when manufacturers finally start releasing fundamentally new models of mass SSDs for personal computers, which will use a faster PCI Express bus instead of the usual SATA 6 Gb / s interface. But the bright moment when the market is flooded with fresh and noticeably more high-performance solutions, everything is postponed and postponed, mainly due to delays in bringing the necessary controllers to mind. The same single models of consumer SSDs with a PCI Express bus, which nevertheless become available, are still clearly experimental in nature and cannot impress us with their speed.

Being in such a languid expectation of changes, it is easy to lose sight of other events that, although they do not have a fundamental impact on the entire industry, are nevertheless important and interesting. Something similar just happened to us: imperceptibly, new trends began to spread in the consumer SSD market, to which we had hardly paid attention until now. SSDs of a new format - M.2 - began to appear on sale in large quantities. A couple of years ago, this form factor was discussed only as a promising standard, but over the past year and a half, it has managed to gain a huge number of supporters among both platform developers and SSD manufacturers. As a result, M.2 drives are not uncommon today, but an everyday reality. They are produced by many manufacturers, they are freely sold in stores and installed everywhere in computers. Moreover, the M.2 format has managed to win a place for itself not only in mobile systems, for which it was originally intended. Many desktop motherboards today are also equipped with an M.2 slot, as a result of which such SSDs are actively penetrating, including classic desktops.

With all this in mind, we have come to the conclusion that it is necessary to pay close attention to M.2 SSDs. Despite the fact that many models of such flash drives are analogues of the usual 2.5-inch SATA SSDs, which are tested by our laboratory on a regular basis, there are also original products among them that do not have twins of the classic form factor. Therefore, we decided to catch up and conduct a unified summary testing of the most popular capacities of 128 and 256 GB available in domestic stores M.2 SSD. Assistance in the implementation of this venture was provided to us by the Moscow company " Regard”, offering an extremely wide range of SSDs, including in the M.2 form factor.

⇡ Unity and Diversity of the World M.2

M.2 slots and cards (previously called Next Generation Form Factor - NGFF) were originally designed as a faster and more compact replacement for mSATA, a popular standard used by solid state drives in various mobile platforms. But unlike its predecessor, M.2 offers fundamentally more flexibility in both logical and mechanical terms. The new standard describes several options for the length and width of cards, and also allows you to use both SATA and faster PCI Express interfaces to connect solid state drives.

There is no doubt that PCI Express will replace the drive interfaces we are used to. The direct use of this bus without additional add-ons allows you to reduce latency when accessing data, and due to its scalability, it significantly increases throughput. Even two PCI Express 2.0 lanes can provide significantly higher data transfer rates compared to the usual SATA 6 Gb / s interface, and the M.2 standard allows you to connect to an SSD using up to four PCI Express 3.0 lanes. The foundation for bandwidth growth thus laid will lead to a new generation of high-speed SSDs capable of faster operating system and application loading, as well as lower latency when moving large amounts of data.

SSD interface	Maximum theoretical bandwidth	Maximum real throughput (estimate)
SATA III	6 Gb/s (750 MB/s)	600 MB/s
PCIe 2.0x2	8 Gbps (1 GB/s)	800 MB/s
PCIe 2.0 x4	16 Gbps (2 GB/s)	1.6 GB/s
PCIe 3.0 x4	32 Gbps (4 GB/s)	3.2 GB/s

Formally, the M.2 standard is a mobile version of the SATA Express protocol described in the SATA 3.2 specification. However, it so happened that over the past couple of years, M.2 has spread much more widely than SATA Express: M.2 connectors can now be found on current motherboards and laptops, and SSDs in the M.2 form factor are widely available for sale. SATA Express is not able to boast of such support from the industry. This is partly due to the greater flexibility of M.2: depending on the implementation, this interface can be compatible with devices using the SATA, PCI Express, and even USB 3.0 protocols. Moreover, in its maximum version, M.2 supports up to four PCI Express lines, while SATA Express connectors can only provide data transfer over two such lines. In other words, today it is M.2 slots that seem not only convenient, but also a more promising foundation for future SSDs. Not only are they suitable for both mobile and desktop applications, they also offer the highest throughput of any existing consumer SSD connectivity options.

However, given the fact that the key property of the M.2 standard is the variety of its types, it should be borne in mind that not all M.2 drives are the same, and their compatibility with various versions of the corresponding slots is a separate story. For starters, commercially available M.2 SSD boards are 22mm wide but come in five lengths: 30mm, 42mm, 60mm, 80mm or 110mm. This dimension is reflected in the marking, for example, the M.2 2280 form factor means that the drive card has a width of 22 mm and a length of 80 mm. For M.2 slots, on the other hand, a complete list of dimensions of drive cards with which they can be physically compatible is usually indicated.

The second feature that differentiates different M.2 variants is the "keys" in the slotted slot and, accordingly, in the knife slot of the cards, which prevent the installation of drive cards in slots that are logically incompatible with them. At the moment, M.2 SSD uses two options for the location of the keys from the eleven different positions described in the specification. Two more options have found use on WLAN and Bluetooth cards in the M.2 form factor (yes, this happens, for example, the Intel 7260NGW wireless adapter), and seven key positions are reserved for the future.

	M.2 slot with type B key (Socket 2)	M.2 slot with M key (Socket 3)
Scheme
Key location	Contacts 12-19	Contacts 59-66
Supported interfaces	PCIe x2 and SATA (optional)	PCIe x4 and SATA (optional)

M.2 slots can only have one partition key, but M.2 cards can have multiple notch keys at once, making them compatible with multiple slot types at the same time. The type B key, located instead of pins 12-19, means that no more than two PCI Express lanes are connected to the slot. The type M key, which occupies pin positions 59-66, means that the slot has four PCI Express lanes and therefore can provide higher performance. In other words, an M.2 card must not only be the right size, but also have a key layout that is compatible with the slot. At the same time, the keys not only limit the mechanical compatibility between various connectors and M.2 form factor boards, but also perform another function: their location prevents the drives from being installed incorrectly in the slot.

The information given in the table should help to correctly identify the type of slot available in the system. But you need to keep in mind that the possibility of mechanical docking of the slot and the connector is only a necessary, but not a sufficient condition for their full logical compatibility. The fact is that slots with keys B and M can be used not only for the PCI Express interface, but also for SATA, but the location of the keys does not provide any information about its absence or presence. The same goes for M.2 card slots.

	Knife connector type B	Knife connector type M	Knife connector with keys type B and M
Scheme
Slot location	Contacts 12-19	Contacts 59-66	Contacts 12-19 and 59-66
SSD interface	PCIe x2	PCIe x4	PCIe x2, PCIe x4 or SATA
Mechanical compatibility	M.2 slot with type B key	M.2 slot with M key	M.2 slots with Type B or Type M keys
Common SSD Models	Not	Samsung XP941 (PCIe x4)	Most M.2 SATA SSDs Plextor M6e (PCIe x2)

There is one more problem. It lies in the fact that many motherboard developers ignore the requirements of the specifications and install the most “cool” M-key slots on their products, but only two of the four PCIe lanes are placed on them. In addition, the M.2 slots available on motherboards may not be compatible with SATA drives at all. In particular, ASUS sins with its love for installing M.2 slots with reduced SATA functionality. SSD manufacturers adequately respond to these challenges, many of which prefer to make both key cutouts on their cards at once, which makes it possible to physically install drives in M.2 slots of any type.

As a result, it turns out that it is impossible to determine the real possibilities, compatibility and availability of the SATA interface in M.2 slots and connectors by external signs alone. Therefore, complete information about the features of the implementation of certain slots and drives can only be obtained from the passport characteristics of a particular device.

Fortunately, at the moment the range of M.2 drives is not so large, so the situation has not had time to get completely confused. In fact, there is only one PCIe x2 M.2 drive model on the market so far, the Plextor M6e, and one PCIe x4 model, the Samsung XP941. All other flash drives available in stores in the M.2 form factor use the familiar SATA 6 GB / s protocol. At the same time, all M.2 SSDs found in domestic stores have two key cutouts - in positions B and M. The only exception is Samsung XP941, which has only one key - in position M, but it is not sold in Russia.

However, if your computer or motherboard has an M.2 slot and you plan to populate it with an SSD, there are a few things you need to check first:

Does your system support M.2 SATA SSD, M.2 PCIe SSD, or both?
If the system has support for M.2 PCIe drives, how many PCI Express lanes are connected to the M.2 slot?
What key layout on the SSD card does the M.2 slot in the system allow?
What is the maximum length of an M.2 card that can be installed in your motherboard?

And only after you can definitely answer all these questions, you can proceed to the selection of a suitable SSD model.

Crucial M500

The Crucial M500 solid state drive in M.2 format is an analogue of the well-known 2.5-inch model of the same name. There are no architectural differences between a “large” flash drive and its M.2 counterpart, which means that we are dealing with low-cost SSDs based on the popular Marvell 88SS9187 controller and equipped with 20nm flash memory manufactured by Micron with 128-gigabit cores . To fit the drive on an M.2 card that measures only 22x80mm, a tighter layout and flash memory chips with denser packing of MLC NAND crystals were used. In other words, the Crucial M500 is hardly capable of surprising anyone with its hardware design, everything in it is familiar and has long been familiar.

For tests, we received two models - with a capacity of 120 and 240 GB. As with 2.5-inch SSDs, their capacities were somewhat reduced from the usual multiples of 16 GB, which means there is a larger spare area, which in this case occupies 13 percent of the total flash memory array. The M.2 versions of the Crucial M500 look like this:

Despite the fact that solid-state drives, that is, SSDs, have appeared for a long time, many users are just starting to learn about them and use them on their computers. Perhaps this is due to the high price and small capacity, although they are faster than standard drives and work much faster.

Before delving into the types of hard drives, their manufacturing technologies, memory types and controllers, it is necessary to focus on the form factor (size). Each of the devices is different in size, has its own connection connectors and is used in completely different ways. If a 2.5-inch SSD does not raise any questions, since it is similar in size and location of connectors to conventional hard drives, then other varieties raise a lot of questions.

Today we will talk about devices such as SSD M.2 drives, what they are, what are their features and advantages. This is a relatively new standard, which, according to many experts, is a revolutionary solution. Let's take a closer look at this topic and find out as much information as possible.

Development of the SATA interface

The SATA interface has become a good replacement for PATA, replacing the wide cable with a more compact, thin and convenient option. The main trend of its development was the desire for compactness, and this is quite normal. Even the new interface required a variation that would allow it to be used in mobile devices and where there are special requirements for the size of components.

Thus, mSATA was created - the same interface, only with more compact dimensions. But he did not live long and he was quickly replaced by a completely new one - the M.2 connector, which had even greater capabilities. Not by mistake, there is no word SATA in the abbreviation, since the new version does not apply to this standard. We will talk about this in more detail later.

The only thing that needs to be said is that the M.2 SSD drive is connected without power cables and cables, thanks to which its use becomes as comfortable as possible and allows the computer to be even more compact. This is one of its key benefits.

Overview of the M.2 interface

M.2 is a connector on an expansion card installed in a PCI-Express slot, or on the motherboard itself. You can install not only M.2 SSDs in it, but other modules, including Bluetooth and Wi-Fi. The scope of this connector is quite wide, which makes it incredibly convenient and useful.

When upgrading your computer, be sure to pay attention to it and install a motherboard with this connector, even if you do not plan to install an SSD with this interface yet.

However, if you have a rather old motherboard and you don't want to change it, for example "GA-P75-D3" with a missing M2 slot, but it has PCI-E 3.0, which has a video card and a PCIe x4 slot. In this case, you can install an SSD on PCIe x4 through a special adapter, but its speed will be slightly lower.

Absolutely all M.2 SSD drives have a recessed mount in M.2 connectors. This form factor provides maximum performance with minimum resource consumption and is designed for the technological improvement of hard drives in the future.

Moreover, as mentioned above, cables and loops are not needed for connection, which usually only take up extra space. In order to start working with the device, simply insert it into the connector.

M-key and B-key

Today's hard drives, including solid state drives, are connected to the SATA bus. The maximum bandwidth of which is 6 Gb / s, that is, approximately 550-600 Mb / s. For a conventional drive, this speed is simply unattainable, but SSD drives can reach much higher speeds without any problems. Only their installation is absolutely meaningless if the interface cannot “pump” data at a higher speed than the one for which it is designed.

In view of this, it became possible to use the PCI-Express bus with a higher bandwidth:

PCI Express 2.0. It has two lines (PCI-E 2.0 x2), is characterized by a throughput of up to 8Gb / s, or about 800Mb / s.
PCI-Express 3.0. It has four lanes (PCI-E 3.0 x4), with a bandwidth of 32Gb/s, or about 3.2Gb/s.

Which interface is used to connect a particular device determines the position of the jumper.

Currently, M.2 SSD drives have the following key options:

B key "Socket2" (includes support for PCI-E ×2, SATA, Audio, USB and other modules).
M key "Socket3" (includes support for PCI-E ×4 and SATA).

For example, we take a motherboard with an M.2 connector with an M-key. That is, the PCIe ×4 bus is used. Can I install a SATA SSD in it? This is an interesting question that we will try to answer.

You need to open the motherboard information and see if it supports M.2 SATA or not. Let's say the manufacturer says yes. In this case, you buy an SSD drive that was originally created for PCIe × 4, and absolutely no problems should arise when connecting.

When choosing a motherboard, be sure to pay attention to whether the M.2 supports the SATA bus so that any hard drive can be used.

Let's summarize all of the above and summarize:

M.2 is simply a different form factor (connector and size) of solid state drives. All motherboards that are equipped with this slot use the PCI-E x4 bus.
The type of bus used by the drive depends on the keys. Typically, a PCI-Express bus (key M) or SATA (key M + B) is used. The ability to connect an SSD with a SATA interface must be indicated in the characteristics of the motherboard.

Size specification: 2260, 2280 and others

Often, when looking through the specification of a computer or laptop motherboard, you can find the following line “1 x M.2 Socket 3, with M Key, type 2260/2280” - it means that 1 M.2 slot with an M key and a size of 2260/2280 is used. The first two digits "22" - mean the width in "mm", the second two digits "60" - this is the length. Therefore, if you choose, say, Transcend TS128GMTS600, with a length of "60mm" and a width of "22mm", then there will be no problems with its installation.

But even if you take the Kingston SHPM2280P2/480G with the “2280” type, and since the motherboard specifications support this type of drive, it will not be difficult to install it.

The motherboard can support many sizes of installed modules and in this case, the fixing screws are placed on it, which are designed for each bar length.

NVMe technology

The old generation of conventional magnetic and SSD drives use the AHCI protocol, which was created a relatively long time ago and is still supported by many operating systems. But with the advent of more modern and faster SSDs, he does not cope with his task and cannot use all their capabilities to the maximum.

The NVMe protocol was created as a solution to this problem. It is characterized by the highest speed, lower latency and uses a minimum of processor resources when performing operations.

In order for the media to work using this technology, it must support it, therefore, when choosing, pay special attention to this, just like the motherboard (it must support the UEFI standard).

Summing up

After we reviewed the M.2 SSD, we can say that this is the most compact form factor of solid state devices. And if it is supported by the motherboard, it is recommended to use it.

Let's look at a few that will help you make the right choice. So, first of all, when buying, you should pay attention to the following points:

Does the motherboard have the required M.2 slot, and what size of modules does it allow (2260, 2280, etc.).
The type of key that the slot uses (M, B, or B+M).
Does the motherboard support SATA or PCI-E interface, and which version is used (for example, PCIe 3.0 4x).
Whether the operating system, the SSD itself and the motherboard support AHCI or NVMe protocols.

Indeed, answering the question of which is better, an SSD with a standard connector or M.2, it is clear that you should choose the second option with NVMe support and install it on PCIe 3.0 × 4.

This will not only free up more space by reducing the number of wires, but will also increase transmission speed, system speed and performance. The main thing is that it will make working at the computer more comfortable, enjoyable and efficient.

Become more and more popular due to the numerous benefits. They are tiny and do not take up much space in a laptop, mini-PC or desktop computer case (they are installed directly on the motherboard), but at the same time, they allow you to achieve speeds that are not available with "regular" 2.5-inch SSDs.

You need to know that M.2 SSD drives are available in various formats (they can vary in length), as well as two main variations - using the SATA interface (cheaper and slower) and using the PCI Express / NVMe interface (more expensive and faster). The currently used SATA interface allows for a maximum throughput of 6 Gb/s, while PCIe x4 up to 32 Gb/s, so the performance difference can be very large, as is the price.

By the way, it is worth mentioning Intel Optane memory (not to be confused with Intel Optane SSD), which has the M.2 media format, but serves to speed up the operation of HDD drives. This technology only works on the newer Intel platforms, but it works surprisingly well, allowing for a significant increase in the speed of magnetic disks.

M.2 connectors on motherboards can support both, or only one - it's worth checking before buying so you don't try to install a PCIe/NVMe drive in a SATA-only M.2 connector, for example. It is worth noting that you can also connect M.2 PCIe drives in the U.2 port (via an adapter), and in the PCI Express slot.

Below are presented as most efficient SSD designs, which use the PCI Express x4 3.0 (NVMe) bus, as well as cheaper / less powerful models that use the SATA standard.

Inexpensive M.2 SSD

Among cheap M.2 drives, how can you find designs that use SATA and PCIe. The capabilities of the former are close to 2.5-inch SSDs, but the size speaks in their favor, as well as the fact that some computers may not serve M.2 NVMe drives.

WD Green PC SSD G2 (120 GB)

The WD Green PC SSD G2 series is one of the cheaper M.2 options. Based on the SATA interface, the 120 GB model achieves 545 MB/s read and 430 MB/s write performance. The manufacturer used a 4-channel Silicon Motion SM2246XT controller and Toshiba 3D TLC NAND memory cells (but without cache memory) here.

Main characteristics:

Disc Format: M.2 2280
Capacity: 120 GB
Disk interface: SATA III
Write speed: 430MB/s
Read speed: 545MB/s
Memory cells: Toshiba 3D TLC NAND

ADATA XPG SX6000 (128 GB)

The ADATA XPG SX6000 is, in turn, one of the cheapest M.2 SSD media using PCIe 3.0 x2. The manufacturer used a Realtek RTS5760 4-channel controller and modern 3D TLC NAND memory here. Claimed speeds reach 730/660 MB/s. A warranty of up to 5 years is provided, but it is limited by the TBW factor (75 TB of data written).

It is worth noting that the 256 GB and 512 GB models are not only affordable, but also much faster (1000/800 MB/s).

Main characteristics:

Disc Format: M.2
Capacity: 128 GB
Interface: PCI-Express 3.0 x2 (NVMe), PCIe 3.0 x2/NVMe 1.2
Write speed: 660MB/s
Read speed: 730MB/s

ADATA Ultimate SU800 M.2 (250 GB)

ADATA Ultimate SU800 M.2 drives are very good value for money. Modern 3D TLC Nand memory cells and a 4-channel Silicon Motion SM2258 controller are used.

This is a SATA drive, so the performance is identical to the 2.5-inch version - read speeds up to 560 MB / s, and writes - 520 MB / s. A 3-year warranty is provided, but is not limited by the TBW factor. Along with the disc, we receive the Acronis True Image HD software package.

Main characteristics:

Capacity: 256 GB
Interface: SATA III M.2
Write speed: 520MB/s
Read speed: 560MB/s
Memory cells: Micron 3D TLC NAND

M.2 SSD for laptop

In the case of laptops, this will often be the only drive in the computer, so it is worth taking care of sufficient capacity - do not invest in an SSD with a capacity below 240/256 GB. We should also pay attention to the type of interface - whether the media supports SATA or PCIe interface, and which format (longer, 2280, or shorter, 2260 or 2242).

Crucial MX500 M.2 (250 GB)

Crucial's latest generation of SATA SSDs, the MX500 is another successful hit in the mid-range performance segment. The M.2 version of the drive performs quite well, with claimed speeds reaching 560 MB/s for reading and 510 MB/s for writing data. Crucial provides a 5 year warranty (limited to 100 TB TBW).

Main characteristics:

Disc Format: M.2 2280
Capacity: 250 GB
Interface: SATA III
Write speed: 510MB/s
Read speed: 560MB/s
Memory cells: Micron 3D TLC NAND

Transcend MTS420 (240 GB)

Transcend MTS420 in 240GB version is a very good suggestion for users who need small format 2242 M.2 media. The manufacturer has listed maximum speeds of 560 MB/s read and 500 MB/s write. It is worth noting that many other discs in this format are characterized by worse characteristics. The manufacturer gives a 3-year warranty on it.

Main characteristics:

Disc format: M.2 2242
Capacity: 240 GB
Interface: SATA III
Write speed: 500MB/s
Read speed: 560MB/s
Memory cells: Micron 3D TLC NAND

ADATA XPG SX8200 (480 GB)

This is a good suggestion for laptop users who can install M.2 2280 PCIe format SSD media in their machine. If the laptop boasts an M.2 PCIe 3.0 x4 connector, the speeds will be 3200 MB / s when reading and 1700 MB / s when writing. The XPG SX8200 drive is covered by a 5-year manufacturer's warranty.

Main characteristics:

Disc Format: M.2 2280
Capacity: 480 GB
Write speed: 1700MB/s
Read speed: 3200MB/s
Memory cells: Micron 3D TLC NAND

Best M.2 SSDs

Best M.2 Drives have amazing performance, and their efficiency is close to the limit of the PCI Express interface (the best of the drives presented here reaches the maximum speed 3.5 GB per second). Obviously, this is reflected in the high price. Such discs can be recommended to professionals, for example, those who work with complex video projects in 4K resolution.

GOODRAM IRDM Ultimate (480 GB)

IRDM Ultimate 480 GB is a good offer for more demanding users. Importantly, the kit includes an adapter for a PCI Express slot. The manufacturer also installed a heat sink that protects the drive from overheating. Onboard is an 8-channel Phison PS5007-E7 controller and durable Toshiba A19 MLC NAND memory cells. Maximum speeds reach 2900/2200 MB/s. The IRDM Ultimate series is covered by a 5-year manufacturer's warranty with no data write limitation.

Main characteristics:

Disc Format: M.2 2280 / AiC HHHL
Capacity: 480 GB
Interface: PCIe 3.0 x4/NVMe 1.2
Write speed: 2200MB/s
Read speed: 2900MB/s
Memory cells:Toshiba A19 MLC NAND

Intel SSD 760p (512 GB)

The Intel SSD 760p is an efficient SSD for desktops and modern laptops using the M.2 connector and PCIe 3.0 x4 interface. On board is a Silicon Motion SM2262 controller and IMFT 3D TLC NAND memory cells. The maximum speeds are 3230 MB/s for reading and 1625 MB/s for writing. The manufacturer provides a 5-year warranty for drives, but limited to TBW (288 TB of recording).

Main characteristics:

Disc Format: M.2
Capacity: 512 GB
Interface: PCI-Express 3.0 x4 (NVMe)
Write speed: 1625MB/s
Read speed: 3230MB/s
Memory cells: IMFT 3D TLC NAND

Samsung SSD 970 EVO (500 GB)

The SSD 970 EVO is Samsung's third generation of high-speed M.2 PCIe storage media. The 970 EVO models are designed for users who are looking for very fast, but not top-of-the-line solutions - this is the combination we will find in the 970 PRO models. The declared read speed reaches 3400 MB / s, and writes - 2300 MB / s. The hard drives of the 970 EVO series are covered by a 5-year manufacturer's warranty - we recall that the warranty period in previous models of the 960 EVO was only 3 years.

Main characteristics:

Disc Format: M.2 2280
Capacity: 500 GB
Interface: PCIe 3.0 x4/NVMe 1.3
Write speed: 2300MB/s
Read speed: 3400MB/s
Memory cells: Samsung TLC V-NAND

Samsung SSD 970 PRO (1TB)

The Samsung 970 PRO 512GB is the absolute top storage M.2 PCIe SSD designed for professionals. The manufacturer used ultra-reliable MLC V-NAND memory here, so users can not be afraid for their data. It is difficult to squeeze even more out of the PCIe 3.0 x4 interface, so the media reaches speeds of 3500 MB / s in reading and 2300 MB / s in writing. The 970 PRO series hard drives are backed by a 5-year manufacturer's warranty.

Main characteristics:

Disc Format: M.2 2280
Capacity: 1000 GB
Interface: PCIe 3.0 x4/NVMe 1.3
Write speed: 2700MB/s
Read speed: 3500MB/s
Memory cells: Samsung MLC V-NAND

Good day.

For several years now, disputes about the benefits of using SSD drives have sunk into oblivion - now it is recommended to install it for everyone: not only professional gamers or programmers, but also ordinary users. The advantage in disk performance is enormous: 5-10 times!

However, now there are quite a lot of SSD drives that differ in size (note: form factor): if there are not so many questions with a 2.5-inch form factor SSD (classic size, looks the same as a hard drive), then there are not so many questions with "newfangled "SSD M2 is a real mess!

Actually, in this article I wanted to analyze the most basic things about SSD M2 drives: which drive is right for me, what interface is used, what kind of 2242, 2260, 2280 it is and the "M", "B", "B & M" keys on the drive label. ..

Choosing an M2 SSD: Dealing with the Confusion

In many new laptops and computers, the new M2 connector has become increasingly common on the motherboard (which is not surprising!). After all, it replaced the interfaces: mSATA, mini PCI Express.

And here I want to immediately note the advantage of the M2 interface: it allows you to do without power cables, separate loops, and other good things (in fact, it allows you to connect devices simply by inserting a card into the slot!). In addition, it is smaller than the same mSATA. All this in a compartment allows M2 to be used in more mobile and compact devices, making it more convenient and popular.

I will add that you can use the M2 to install a Wi-Fi adapter, 3G / 4G modems, a Bluetooth module, and other devices. (Note: it's just that many people think that M2 is used exclusively for SSD)

By the way!

The M2 interface was at one time referred to as NGFF (Next Generation Form Factor). In some stores and some drive manufacturers, there are M2 SSDs with this marking.

What is the confusion

1) SATA and PCIe

The M2 format, of course, is undeniably promising, but everything is not easy with it. I must say right away that it is divided into two large types: SATA and PCIe (and each of these types is divided into several subtypes).

Why was this done? M2, as I said above, was conceived as a universal interface that will replace the outdated mSATA and mini PCIe. But, the fact is that the bandwidth of SATA III is 6 Gb / s, and the SSD M2 PCIe drive is capable of providing speeds up to 32 Gb / s (you must agree, the difference is significant!).

I will add that M.2 PCIe varies in speed depending on the number of lanes. So, for example, PCI Express 2.0 with two lines (referred to as PCI-E 2.0 x2) - provides speeds up to 8 Gb / s, PCI Express 3.0 with four lines (PCI-E 3.0 x4) - provides the coveted 32 Gb / s.

The good news is that most devices (let's say laptops) only support one type of drive, such as an M2 SATA III SSD. Those. when choosing, you need to be very careful about what the device supports (but a couple of words about this below).

2) Drive dimensions 2242, 2260 and 2280

Another important point: M2 drives (both SATA and PCIe) can be of different sizes. There are three of them: 2242, 2260 and 2280.

The first two digits (22) are the width of the drive, the second (42, 62 or 80) are its length (see the screenshot below as an example).

The bottom line is that different motherboards support different sizes of drives. And if a disk of a shorter length can still be inserted into the slot, then if it is longer, this is a disaster ...

However, I note that now there are universal disks on sale, 80 mm long, which you can cut yourself to the desired length (note: all the necessary microcircuits are located at a length of 42 mm).

3) Keys

Keys are contacts and their location on the drive. There are three types of keys: "M", "B", and the universal "B&M" (illustrative example below). Before buying a drive, you need to know which key is supported by your device.

Drives with different keys, a good example

Keys on SSD M2 drives: interface, mechanical compatibility, scheme

All the "salt" with these keys is that, for example, a mat. The PCIe x2 socket board uses the "B" key, but there are M2 SATA SSDs that also use the "B" key! Of course, if you connect such a drive to a motherboard with a PCIe x2 socket, it will not work!

4) NVMe technology

Old drives use the AHCI protocol, but with the advent of faster drives, it has ceased to cope with its task (it does not allow using the maximum speed characteristics of the drives). To solve this problem, a new protocol has been released - NVMe.

It provides higher speed, requires less resources from the processor during read / write operations, and has much less latency. In order for your SSD to work on this protocol, pay attention to whether your mat. payment for this technology.

Results (what to know before buying an SSD M2, so as not to be in the "fools"):

what interface does your motherboard support (PCI-E 2.0 x4, PCI-E 3.0 x2, PCI-E 3.0 x4, SATA III);
dimensions of the SSD M2 drive that can be installed (2280, 2260, 2242);
a key that your motherboard supports (usually, SATA drives come with an "M&B" key, and PCIe x4 with an "M" key);
is mat supported? board NVMe technology (if yes, then naturally, and the drive should be bought with NVMe support).

Only after answering these few questions, you can choose the SSD M2 that will work for you.

Update from 01/27/2019. Now laptops (and motherboards) with universal ports have begun to appear on sale, to which you can connect an M2 SSD both PCI-E and SATA.

Is the game worth the candle? Should I switch to SSD...

Many people often ask whether it is worth switching to an SSD at all, is the difference really that significant ...

As an example, I will show a comparative test of several disks installed on my laptops / PCs. The first test is SSD M2 (NVMe), the second is SSD M2 (SATA III), the third is a classic HDD.

SSD (NVMe, SATA), HDD speed test | Clickable (Crystal DiskMark - test utility)

Note! On the screenshots you see synthetic tests. In real work (when loading the OS, running games, working with software): many of the average users notice a huge difference between HDD and SSD (SATA), but hardly notice between SSD (NVMe) and SSD (SATA).

Pay attention to the first line. Reading speed (Read) 2591 MB/s versus 73 MB/s - 30÷35 times difference! Those. if earlier, before installing the SSD (NVMe), Windows loaded within 1 minute - now it's less than 10 seconds!

I'm not talking about other programs: Word, browsers, players, etc. - run instantly, immediately after double-clicking on the shortcut!

Addition!

How to check disk speed: HDD, SSD. Test, determining the difference in speed between SSD and HDD, is it worth switching to a solid state drive -

How do I find out which M2 SSD my mate supports. board what to choose

A very popular question. To begin with, I want to say do not trust any utility for viewing PC characteristics. The fact is that they can show the presence of an M2 slot, but in fact it may not be on the board. (i.e. there is a place on the board for it, but there is no physical slot)!

And so, more to the point ...

1) Option number 1 - look at the mat itself. board.

If on your mat. board has an M2 connector - then in most cases there is a marking next to it, by which you can find out the necessary information (example below). In addition, immediately make sure that this connector is physically present (which is important to do before buying a drive).

2) Option number 2 - look at the manufacturer's website

Knowing the model of the motherboard (or laptop), you can go to the website of its manufacturer and see the characteristics. By the way, some motherboards are now being made universal, which can support several types of M2 SSD drives (laptop users are less fortunate in this case, because they most often support one specific type).

Characteristics mat. boards on the manufacturer's website

3) Option number 3 - see an overview of a specific laptop (motherboard).

Many stores and users (who have already purchased this hardware) often make reviews from which you can get the necessary data. However, I recommend to reinforce them also with the first two options (because to say, see for yourself).

Additions are welcome...

M.2 connector (formerly known as Next Generation Form Factor and NGFF) is a specification included in the SATA 3.2 standard for computer devices and their connectors, approved by the Serial ATA International Organization (SATA-IO) for tablets and thin computers. Designed to replace the already obsolete SATA, mSATA and Mini PCI-E formats. The key innovation of M.2 (NGFF) was the support for data transfer over the PCI Express 3.0 line with a total theoretical bandwidth of up to 32 Gb / s. Which is almost 6 times more than the SATA 3.0 standard allowed.

M.2 expansion cards can provide various features such as Wi-Fi, Bluetooth, satellite navigation, NFC radio, digital radio, Wireless Gigabit Alliance (WiGig), Wireless WAN(WWAN) and others. M.2 modules are often used as fast and compact solid-state flash drives (SSDs).

The use of a new device format made it possible to use the DevSleep minimum power mode, the Transitional Energy Reporting power management mechanism, the Hybrid Information mechanism (which increases the efficiency of data caching in hybrid drives) and Rebuild Assist (a function that speeds up the data recovery process in RAID arrays).

Form factor and keys.

Simply put, M.2 is a mobile version of the SATA Express protocol described in the SATA 3.2 specification for tablets and thin computers. This interface can be compatible with SATA, PCI Express, USB 3.0, I2C and other devices. M.2 supports up to four PCI Express 3.0 lanes, while SATA Express connectors only transfer data over two PCI Express 2.0 lanes. The boards are available in 4 widths (12, 16, 22 and 30mm) and 8 lengths (16, 26, 30, 38, 42, 60, 80 and 110mm).

In addition to the length and width of devices connected to M.2, the standards for the thickness of components on the board are described. Also, single-sided and double-sided mounting (Single Sided and Double Sided), divided into 8 more types. For easier understanding, below is a table:

The thickness of the components on the board of the device connected to M.2 (dimensions are in millimeters).

Type	Above	Bottom
S1	1.20	Not allowed
S2	1.35	Not allowed
S3	1.50	Not allowed
D1	1.20	1.35
D2	1.35	1.35
D3	1.50	1.35
D4	1.50	0.70
D5	1.50	1.50

To indicate the M.2 type, devices are marked with a code according to the scheme WWLL-HH-K-K or WWLL-HH-K, where WW and LL are the dimensions of the module in width and length in millimeters. HH encodes whether the module is single-sided or double-sided, as well as the maximum allowable height (thickness) of the components placed on it, for example, "D2". The K-K part denotes key cuts. If the module uses only one key, one letter K is used. If K-K is used, then the module has 2 keys.

A diagram with a detailed breakdown of all marking values with indication of the values.

As of 2018, the most popular sizes are: width 22 mm, length 80 or 60 mm (M.2-2280 and M.2-2260), rarely 42 mm. Many early M.2 drives and motherboards used the SATA interface, and dongles are the most popular for them. B(SATA and PCIe x2). Modern motherboards implement in the M.2 PCI Express 3.0 x4 slot and the corresponding key M(SATA and PCIe x4). Devices designed for use in sockets with the M key are not electrically compatible with socket B, and vice versa, unless explicitly stated. Although not rare, as practice shows, they are physically compatible (if turned over). To connect expansion cards, such as WiFi, 1630 and 2230 size modules and dongles are used. A or E.

M.2 - the board must not only fit in size, but also have a key arrangement compatible with the slot. Keys restrict mechanical compatibility between different M.2 connectors and boards and prevent drives from being misplaced in a slot.

Actually, before buying an expansion board, you need to check with the manufacturer the type of connector and compatible dimensions (length, width, thickness, one-sided and two-sided execution).

What is Socket 1, Socket 2, Socket 3 in relation to M.2 (NGFF) devices?

Indeed, the concept of a socket is also used for M.2 devices. I think the creation of groups of M.2 connectors on Socket 1,2,3 to simplify the separation of incompatible devices. Formally dividing all types of devices into 3 easy-to-understand types.

The principle of division is clearly shown in the following table:

	For installation in an M.2 slot
	Connector Key	Module size	Module thickness	Connector key on module
Socket 1 Usually, communication modules (WIFi adapters, Bluetooth, NFC, etc.)
	A, E	1630	S1, D1, S3, D3, D4	A, E, A+E
	A, E	2230	S1, D1, S3, D3, D4	A, E, A+E
	A, E	3030	S1, D1, S3, D3, D4	A, E, A+E
Socket 2 For compact 3G/4G M.2 modems, but other equipment may be available	B	3042	S1, D1, S3, D3, D4	B
Socket 2 For M.2 SSD and other equipment with B+M Generic Key	B	2230	S2, D2, S3, D3, D5	B+M
	B	2242	S2, D2, S3, D3, D5	B+M
	B	2260	S2, D2, S3, D3, D5	B+M
	B	2280	S2, D2, S3, D3, D5	B+M
	B	22110	S2, D2, S3, D3, D5	B+M
Socket 3 For M.2 SSD and other equipment with M key and B+M universal key	M	2242	S2, D2, S3, D3, D5	M, B+M
	M	2260	S2, D2, S3, D3, D5	M, B+M
	M	2280	S2…D2, S3, D3, D5	M, B+M
	M	22110	S2…D2, S3, D3, D5	M, B+M

Let's analyze an example based on real online stores:

SSD SAMSUNG M.2 860 EVO 250GB M.2 2280 SATA III (MZ-N6E250BW)

From the description it can be seen that we have a Samsung SSD with a capacity of 250Gb, designed for use in the M.2 connector. Next comes the marking "2280" indicating the physical size - 22 mm wide, 80 mm long. Not a word about the thickness and one-sided or two-sided execution. In this case, you will have to clarify from other sources, or the manufacturer of the drive. After specifying the size marking, it says - SATA III. What does this mean? This means that the drive uses a SATA III logical interface. That is, we have the same classic SATA drive, but made to fit the dimensions and the M.2 connector. The speed advantages of PCI Express are not used here.

Everything, the description of the seller on this exhausted. What are we still missing? We lack an explicit indication of the type of connector key, let it remain on the conscience of the seller. But we visually see 2 slots, which means that this drive can be used as part of motherboards with a connector like B and type M. This is a visual assessment, I repeat again - you need to check with the manufacturer.

Let's try again:

SSD disk Samsung 960 EVO M.2 250 GB M.2 PCI-E TLC MZ-V6E250BW

Here we see the Samsung 960 EVO SSD also on the M.2 connector. In general, without indicating the marking of physical dimensions and type, presumably also "2280" (it is always necessary to clarify from other sources). The following are PCI-E and TLC, what does this mean? This means that the device uses a PCI Express logical interface (which 2.0 or 3.0 is not clear, and how many 2x-4x lanes is also unknown). TLC is a device type of memory chips. On this, the online store considered the description sufficient. I think the warranty will tell him later about the opposite ...

But visually, in this image, we see one slot in the M.2 connector (presumably corresponding to the key M). And here you need to be careful, the device can physically fit into the connector B. And most likely, it will burn the board and the device. Therefore, it is necessary to know exactly what type of connector is installed on the board and which one is being purchased.

Implementations of the logical interface and command set.

For M.2 expansion cards, there are three options for implementing a logical interface and a set of commands, similar to the SATA Express standard:

"Legacy SATA" Used for SSD with SATA interface, AHCI driver and speeds up to 6.0Gbps (SATA 3.0) "SATA Express" using AHCI Used for SSD with PCI Express interface and AHCI driver (for compatibility with more operating systems) . Due to the use of AHCI, performance may be slightly less than optimal (obtained with NVMe), since AHCI was designed to work with slower drives with slow sequential access (for example, HDD), and not for SSDs with fast random access. "SATA Express" using NVMe Used for PCI Express SSDs with a high performance NVMe driver designed to work with fast flash drives. NVMe was designed with the low latency and parallelism of PCI Express SSDs in mind. NVMe makes better use of parallelism in host and software, requires fewer stages in data transfer, provides deeper command queuing, and more efficient interrupt handling.

What is NVM?

NVM Express ( NVMe, NVMHCI - from English. Non-Volatile Memory Host Controller Interface Specification). The NVM Express logical interface has been designed from the ground up to achieve low latency and efficient use of the high parallelism of SSDs through the use of a new instruction set and queuing engine optimized to work with modern multi-core processors.

The NVMe protocol speeds up I/O operations by eliminating the SAS command stack (SCSI). NVMe SSDs plug directly into the PCIe bus. Applications get a dramatic performance boost from shifting I/O activity from SAS/SATA SSD and HDD to NVMe SSD. Memory devices of a new type of storage are nonvolatile (non-volatile) and the delay in accessing them is much lower - at the level of delays in random access (volatile) memory.

The NVMe controller demonstrates all the advantages of SSD: very low access latency and huge queue depth for read and write operations. The extremely low latency of storage devices significantly reduces the chances of data table locks during table updates. This is critical for multi-user databases with complex and interrelated tables.

Very important: the UEFI BIOS of the motherboard must contain an NVMe driver to boot the OS from the appropriate drive.

Pinout of typical M.2 connectors.

M.2 Key B (1x SATA, 2x PCIe)

Pin number	Pin Name	Description
1	CONFIG_3	Defines module type
2	3.3V	Supply pin, 3.3V
3	GND	Ground
4	3.3V	Supply pin, 3.3V
5	N/C
6-8	N/A
9	N/C
10	DAS/DSS
11	N/C
12-19	removed	Mechanical notch B
20	N/A
21	CONFIG_0	Defines module type
22-26	N/A
27	GND	Ground
28	N/A
29	PERn1	PCIe Lane 1 Rx
30	N/A
31	PERp1	PCIe Lane 1 Rx
32	N/A
33	GND	Ground
34	N/A
35	PETn1	PCIe Lane 1 Tx
36	N/A
37	PETp1	PCIe Lane 1 Tx
38	DEVSLP
39	GND	Ground
40	N/A
41	SATA-B+/PERn0
42	N/A
43	SATA-B-/PERp0	Host receiver differential signal pair. If in PCIe mode PCIe Lane 0 Rx
44	N/A
45	GND	Ground
46	N/A
47	SATA-A-/PETn0
48	N/A
49	SATA-A+/PETp0	Host transmitter differential signal pair. If in PCIe mode PCIe Lane 0 Tx
50	PERST#	PCIe reset
51	GND	Ground
52	CLKREQ#
53	REFCLKN
54	PEWAKE#
55	REFCLKP	PCIe Reference Clock signals (100 MHz)
56	MFG1
57	GND	Ground
58	MFG2	manufacturing pin. Use determined by vendor.
59-66	removed	mechanical notch M
67	N/A
68	SUSCLK
69	CONFIG_1	Defines module type
70	3.3V	Supply pin, 3.3V
71	GND	Ground
72	3.3V	Supply pin, 3.3V
73	GND	Ground
74	3.3V	Supply pin, 3.3V
75	CONFIG_2	Defines module type

M.2 with M key (1x SATA, 1x, 2x, or 4x PCIe)

Pin number	Pin Name	Description
1	CONFIG_3	Defines module type
2	3.3V	Supply pin, 3.3V
3	GND	Ground
4	3.3V	Supply pin, 3.3V
5	PERn3	PCIe Lane 3 Rx
6	N/A
7	PERp3	PCIe Lane 3 Rx
8	N/A
9	GND	Ground
10	DAS/DSS	Device Activity Signal / Disable Staggered Spinup
11	PETn3	PCIe Lane 3 Tx
12	3.3V	Supply pin, 3.3V
13	PETp3	PCIe Lane 3 Tx
14	3.3V	Supply pin, 3.3V
15	GND	Ground
16	3.3V	Supply pin, 3.3V
17	PERn2	PCIe Lane 2 Rx
18	3.3V	Supply pin, 3.3V
19	PERp2	PCIe Lane 2 Rx
20	N/A
21	CONFIG_0	Defines module type
22	N/A
23	PETn2	PCIe Lane 2 Tx
24	N/A
25	PETp2	PCIe Lane 2 Tx
26	N/A
27	GND	Ground
28	N/A
29	PERn1	PCIe Lane 1 Rx
30	N/A
31	PERp1	PCIe Lane 1 Rx
32	N/A
33	GND	Ground
34	N/A
35	PETn1	PCIe Lane 1 Tx
36	N/A
37	PETp1	PCIe Lane 1 Tx
38	DEVSLP	Device Sleep, input. If driven high the host is informing the SSD to enter a low power state.
39	GND	Ground
40	N/A
41	SATA-B+/PERn0	Host receiver differential signal pair. If in PCIe mode PCIe Lane 0 Rx
42	N/A
43	SATA-B-/PERp0	Host receiver differential signal pair. If in PCIe mode PCIe Lane 0 Rx
44	N/A
45	GND	Ground
46	N/A
47	SATA-A-/PETn0	Host transmitter differential signal pair. If in PCIe mode PCIe Lane 0 Tx
48	N/A
49	SATA-A+/PETp0	Host transmitter differential signal pair. If in PCIe mode PCIe Lane 0 Tx
50	PERST#	PCIe reset
51	GND	Ground
52	CLKREQ#	Reference clock request signal
53	REFCLKN	PCIe Reference Clock signals (100 MHz)
54	PEWAKE#	PCIe WAKE# Open Drain with pull up on platform. Active low.
55	REFCLKP	PCIe Reference Clock signals (100 MHz)
56	MFG1	manufacturing pin. Use determined by vendor.
57	GND	Ground
58	MFG2	manufacturing pin. Use determined by vendor.
59-66	removed	mechanical notch M
67	N/A
68	SUSCLK	32.768 kHz clock supply input provided by the Platform chipset
69	CONFIG_1	Defines module type
70	3.3V	Supply pin, 3.3V
71	GND	Ground
72	3.3V	Supply pin, 3.3V
73	GND	Ground
74	3.3V	Supply pin, 3.3V
75	CONFIG_2	Defines module type

M.2 with A (PCIe ×2, USB 2.0, I2C and DP ×4) and E (PCIe ×2, USB 2.0, I2C, SDIO, UART and PCM) key.

pin id.	Pin name	Description
		Ground
	3.3V	3.3V power supply
	USB_D+	USB high-, full-, and low-speed data pair positive
	3.3V	3.3V power supply
	USB_D-	USB high-, full-, and low-speed data pair negative
	LED1#
		Ground

		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
	LED2#
		Do not connect
		Ground
		Do not connect
		Do not connect
		Do not connect
		Do not connect
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Substrate removed to act as physical key
		Do not connect
		Ground
		Do not connect
	PETp0	PCI Express lane 0 module transmitter pair positive
		Do not connect
	PETn0	PCI Express lane 0 module transmitter pair negative
	Vendor defined
		Ground
	Vendor defined
	PERp0	PCI Express lane 0 module receiver pair positive
	Vendor defined
	PERn0	PCI Express lane 0 module receiver pair negative
	COEX3	Antenna coexistence signal 3
		Ground
	COEX2	Antenna coexistence signal 2
	PEFCLKP0	PCI Express reference clock pair positive
	COEX1	Antenna coexistence signal 1
	PEFCLKN0	PCI Express reference clock pair negative
	SUSCLK	32.768 kHz clock module input
		Ground
	PERST0#	PCI Express reset
	CLKREQ0#	PCI Express clock request
	W_DISABLE2#	Wireless disable 2
	PEWake0#	PCI Express wake
	W_DISABLE1#	Wireless disable 1
		Ground
	SMB_DATA	SMBus data signal
	Reserved
	SMB_CLK	SMBus clock signal
	Reserved
	ALERT#	SMBus alert signal
		Ground
	Reserved
	Reserved
	UIM_SWP
	Reserved
	UIM_POWER_SNK
		Ground
	UIM_POWER_SRC
	Reserved
	3.3V	3.3V power supply
	Reserved
	3.3V	3.3V power supply
		Ground

Conclusion.

In conclusion, the advantages adopted by the SATA 3.2 standard become apparent. The emergence of new specifications and connectors will expand the choice of compatible expansion cards for both laptops and desktop computers. It will also increase the overall performance of computing systems from a laptop to a server.

The interface itself is fraught with a large number of traps for both a simple user and a professional. Perhaps this is due to its novelty, and maybe some "dampness".

In any case, I tried to collect as much important information as possible. Any questions can be asked in the comments to the article. If the article helped you, you can thank me by sending donations to Yandex wallet, the form for sending money is at the very bottom of the site (footer). Thank you for your attention to my article.