M.2 questions

[Mr.Reggin]

So are all M.2 slots the same, 'cause I heard that there are some differences too? Can I also use mSATA SSDs on m.2?

[olback]

there is Pci-express and sata i think 

[Aniallation]

So are all M.2 slots the same, 'cause I heard that there are some differences too? Can I also use mSATA SSDs on m.2?

M.2 slots are the same as they're just PCIe, but the length of M.2 SSDs are different, with different form factors based on what you're installing it in. 

 

No, mSATA SSDs will not work in an M.2 slot.

[Tiby]

mSATA is different then M.2 and yes there are two connectors for it. 

You can read a bit more about it on this wiki article.

[Alibaladin]

So are all M.2 slots the same, 'cause I heard that there are some differences too? Can I also use mSATA SSDs on m.2?

M.2

From Wikipedia, the free encyclopedia

For other uses, see M2.

Size comparison of mSATA (left) and M.2 (size 2242, right) SSDs

M.2, formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion cards and associated connectors. It replaces the mSATA standard, which uses the PCI Express Mini Card physical layout. M.2's more flexible physical specification that allows different module widths and lengths, together with more advanced features, makes the M.2 more suitable for solid-state storage applications in general, especially when used in small devices like ultrabooks or tablets.^[1]

Computer bus interfaces provided through the M.2 connector, together with supported logical interfaces, are a superset to those defined by the SATA Express interface. Essentially, the M.2 standard is a small form factor implementation of the SATA Express interface (which provides support for PCI Express 3.0 and Serial ATA 3.0), with the addition of an internal USB 3.0 interface. The M.2 connector can have different keying notches that denote various uses of M.2 modules.^[1][2]

Contents

• 1 Features
• 2 Form factors and keying
• 3 See also
• 4 References
• 5 External links

Features

Multiple functions are supported for add-in cards, including the following device classes: Wi-Fi, Bluetooth, satellite navigation, near field communication (NFC), digital radio, Wireless Gigabit Alliance (WiGig), wireless WAN (WWAN), and solid-state drives (SSDs). Exposed buses are PCI Express 3.0, Serial ATA 3.0 and USB 3.0, which is backward compatible with USB 2.0. The SATA revision 3.2 specification, in its gold revision as of August 2013, standardizes the SATA M.2 as a new format for storage devices and specifies its hardware layout.^[3][4]

The M.2 specification provides four PCI Express lanes and one SATA 3.0 6 Gbit/s port, exposed through the same connector, allowing use of both PCI Express and SATA storage devices in form of M.2 cards. Exposed PCI Express lanes provide a pure PCI Express connection to the storage device, without any additional layers of abstraction.^[5]PCI-SIG M.2 specification, in its revision 1.0 as of December 2013, provides detailed M.2 specifications.^[6]

There are three options available for the logical device interfaces and command sets used for interfacing with M.2 storage devices, provided as features of the SATA Express storage interface:^[5][7]

Legacy SATA Used for SATA SSDs, and interfaced through the AHCI driver and legacy SATA 3.0 6 Gbit/s port exposed through the M.2 connector. SATA Express using AHCI Used for PCI Express SSDs and interfaced through the AHCI driver and provided PCI Express lanes, providing backward compatibility with widespread SATA support in operating systems at the cost of not delivering optimal performance by using AHCI for accessing PCI Express SSDs. AHCI was developed back at the time when the purpose of a host bus adapter (HBA) in a system was to connect the CPU/memory subsystem with a much slower storage subsystem based on rotating magnetic media; as such, AHCI has some inherent inefficiencies when applied to SSD devices, which behave much more like DRAM than like spinning media. SATA Express using NVMe Used for PCI Express SSDs and interfaced through the NVMe driver and provided PCI Express lanes, as a high-performance and scalable host controller interface designed and optimized especially for interfacing with PCI Express SSDs. NVMe has been designed from the ground up, capitalizing on the low latency and parallelism of PCI Express SSDs, and fulfilling the parallelism of contemporary CPUs, platforms and applications. At a high level, the basic advantages of NVMe over AHCI relate to NVMe's ability to exploit parallelism in host hardware and software, based on its design advantages that include data transfers with fewer stages, greater depth of command queues and more efficient interrupts processing. Form factors and keying

The M.2 standard is designed as a revision and improvement to the mSATA standard, allowing for larger printed circuit boards (PCBs) to be manufactured. While mSATA took advantage of the existing PCI Express Mini Card form factor and connector, M.2 has been designed to maximize usage of the card space while minimizing the footprint. As the result of the M.2 standard allowing longer modules and double-sided component population, M.2 devices can provide double the storage capacity within the footprints of mSATA SSD devices.

M.2 modules are rectangular, with an edge connector on one side (75 positions with up to 67 pins, 0.5 mm pitch, pins overlap on different sides of the PCB), and a semicircular mounting hole at the center of the opposite edge. Each pin on the connector is rated for up to 50 V and 0.5 A, while the connector itself is specified to endure up to 60 mating cycles. The M.2 standard allows module widths of 12, 16, 22 and 30 mm, and lengths of 16, 26, 30, 38, 42, 60, 80 and 110 mm. Initial line-up of the commercially available M.2 expansion cards is 22 mm wide, with varying lengths of 30, 42, 60, 80 and 110 mm.^[1][2][8][9]

An M.2 module is installed into a mating connector provided by the host's circuit board, and a single mounting screw secures the module into place. Components may be mounted on either side of the module, with the actual module type limiting how thick components can be; maximum allowable thickness of components is 1.5 mm per side. Different host-side connectors are used for single- and double-sided M.2 modules, providing different amounts of space between the M.2 expansion card and the host PCB.^[2][8] Host circuit boards usually support multiple lengths of M.2 modules, meaning that the sockets capable of accepting longer M.2 modules usually also accept shorter ones by providing different positions for the mounting screw.^[10]

M.2 cards keying and provided interfaces^[2]:8[8]:3 Key

ID Notched

pins Provided interfaces A 8–15 PCIe ×2, USB 2.0, I²C and DP ×4 B 12–19 PCIe ×2, SATA, USB 2.0 and 3.0, Audio, PCM, IUM, SSIC and I²C C 16–23 Reserved for future use D 20–27 Reserved for future use E 24–31 PCIe ×2, USB 2.0, I²C, SDIO, UART and PCM F 28–35 Future Memory Interface (FMI) G 39–46 Generic (not used in M.2 specification) H 43–50 Reserved for future use J 47–54 Reserved for future use K 51–58 Reserved for future use L 55–62 Reserved for future use M 59–66 PCIe ×4 and SATA Maximum components thickness on M.2 cards (in millimeters)^[2]:8[8]:3 Type

ID Top side Bottom side S1 1.20 N/A S2 1.35 N/A S3 1.50 N/A 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

M.2 keying notches in B and M positions; overlapping of the pins on different sides of an M.2 module is also visible

PCB of an M.2 module provides a 75-position edge connector; depending on the type of module, certain pin positions are removed to present one or more keying notches. Host-side M.2 connectors may populate one or more mating key positions, determining that way the type of modules accepted by the host; as of April 2014, host-side connectors are available with only one mating key position populated (either B or M).^[2][8][11] For example, M.2 modules with two notches in B and M positions use up to two PCI Express lanes and provide broader compatibility at the same time, while M.2 modules with only one notch in the M position use up to four PCI Express lanes; both examples also support SATA storage devices. Similar keying applies to M.2 expansion cards that utilize provided USB 3.0 connectivity.^[2][11][12]

Various types of M.2 devices are denoted with WWLL-HH-K-K or WWLL-HH-K codes, where WW and LL specify the module width and length, respectively, in millimeters. Part HH specifies, in an encoded form, whether a module is single- or double-sided, and the maximum allowed thickness of mounted components; possible values are listed in the right table above. Module keying is specified by the K-K part, in an encoded form by using key IDs from the left table above; it can also be specified as K only, if a module has only one key.^[2][8]

Beside socketed expansion cards, the M.2 standard also includes support for permanently soldered single-sided modules.^[8]

[Alibaladin]

[TheMcSame]

So are all M.2 slots the same, 'cause I heard that there are some differences too? Can I also use mSATA SSDs on m.2?

M.2 slots are NOT all the same, there are different slots. IIRC the slot type DOES matter. As an example, the EVGA X99 classified has two M.2 slots, one is slot E and the other is slot M.

 

mSATA can't be used in M.2 slots.

[Mr.Reggin]

M.2 slots are NOT all the same, there are different slots. IIRC the slot type DOES matter. As an example, the EVGA X99 classified has two M.2 slots, one is slot E and the other is slot M.

 

mSATA can't be used in M.2 slots.

can i use the m.2 ssd on both m.2's. Are there msata to m.2 adapters?

[TheMcSame]

can i use the m.2 ssd on both m.2's. Are there msata to m.2 adapters?

Seeing as they've bothered to separate the different slots I'd say no. Only on the same key that the SSD is.

 

"Are there any mSATA to m.2 adapters?"

 

Possibly? I've had a look and I can't really find anything, but you can get mSATA to SATA adapters.

[Mr.Reggin]

Seeing as they've bothered to separate the different slots I'd say no. Only on the same key that the SSD is.

 

"Are there any mSATA to m.2 adapters?"

 

Possibly? I've had a look and I can't really find anything, but you can get mSATA to SATA adapters.

can i use an m.2 ssd on an m.2 slot that runs over pcie

[TheMcSame]

can i use an m.2 ssd on an m.2 slot that runs over pcie

As long as it's the right slot type then yes. I'm pretty most, if not all M.2 slots run over PCIe.