Detailed information about all M.2 SSD form factors, including a large list of compatible Ultrabooks, notebooks and desktop systems.

This post is an attempt to dispel any confusion around the new M.2 SSD format, and has been developed as a resource for RamCity staff, customers and anyone else with an interest. A special mention needs to go Kent Smith of LSI. Thisblog post he wrote helped clarify some of the finer points contained here.

Installing Windows on the Samsung XP941 PCIe M.2 SSD

One of the most common questions we get is how to get Windows installed onto the Samsung XP941. Put simply, it can't be installed from the Windows DVD, but it is possible with these instructions.

M.2 SSD Form Factors

M.2 form factors vary in length and width, with the chips usually populating just one side of the circuit board to keep the drive profile extremely low (less then 3mm). Commercially available M.2 SSD drive lengths include 30mm, 42mm, 60mm, 80mm, and 110mm. These measurements are commonly expressed like '2242' (meaning 22mm wide, 42mm long), or '2280', meaning 22mm wide, and 80mm long.

It's all about the keys

A 'key' defines both the socket (female) and the plug-in card connector (male). In the context of an M.2 SSD, the key prevents the insertion of a connector into an incompatible socket to ensure the proper mating of the two. Currently the M.2 specification for SSDs uses just 2 out of 11 defined key configurations, with seven for use sometime in the future, and 2 used for other devices such as WLAN and Bluetooth adapters like the Intel 7260NGW wireless adapter.

An M.2 SSD socket can only have one type of key, but an M.2 SSD drive can have keyways cut for multiple keys if it supports those socket types. Key ID B (pins 12-19) gives PCIe SSDs up to two lanes (PCIe x2) of connectivity and key ID M (pins 59-66) provides PCIe SSDs with up to four lanes (PCIe x4) of connectivity and correspondingly higher performance. Note also that both B and M keys can accommodate SATA devices. All of the key patterns are different from one another so that the card has to be the right way up and cannot be inserted incorrectly.

Not all keys are the same

The rest of the information here will help you identify the type of M.2 key deployed in your system. However, since 'B' and 'M' type keys can support either PCIe or SATA signalling, knowing the key alone is not sufficient information to determine the correct M.2 SSD upgrade path for your system. You'll need to carefully study your system specifications manual to see if the socket is SATA or PCIe. Fortunately the limited number of M.2 SSD drives available does narrow the choices down somewhat. Further down we also have a list of known systems and the associated compatible M.2 SSD type it needs.

M.2 SSD Sockets

The table below shows the different types of M.2 SSD sockets found in M.2 compatible systems and motherboards:

M.2 (NGFF) Socket
Comparison Chart

Socket for 'B' Key Edge Connector

Socket for 'M' Key Edge Connector

6 contacts wide 5 contacts wide
Pin Position
Pins 12-19
Pins 59-66
Supported Drive Type
PCIe x2 / SATA
PCIe x4 / SATA
Typical Application
PCIe x2 M.2 / SATA M.2
PCIe x4 M.2

M.2 SSD Drive Edge Connectors

The table below shows the different types of edge connectors deployed on different models of M.2 SSD Drives

M.2 (NGFF) Edge Connector
Comparison Chart

'B' Key SSD Edge Connector

'M' Key SSD Edge Connector

'M' & 'B' Key SSD Edge Connector

6 contacts wide 5 contacts wide 6 contacts wide5 contacts wide
Pin Position
Pins 12-19
Pins 59-66
Pins 59-66 (M) & Pins 12-19 (B)
Supported Drive Type
PCIe x2 / SATA
PCIe x4 / SATA
PCIe x2 / PCIe x4 / SATA
Typical Application
PCIe x2 M.2
PCIe x4 M.2
SATA M.2
M.2 SSD Models
None that we know of
Samsung XP941 (PCIe x4)
MyDigitalSSD SuperCache 2 M.2 (SATA)
Crucial M500/M550 M.2 (SATA)
Plextor M6e M.2 (PCIe x2)

So which M.2 SSD Drive do I need?

If you are planning to upgrade your system with a larger or brand new M.2 SSD, you are going to need to figure out several things:

  • Whether your system supports M.2 SATA or M.2 PCIe
  • If it is M.2 PCIe, whether it's PCIe x2 or PCIe x4
  • The type of key supported by the socket
  • The maximum length of SSD drive supported (from 42mm up to 110mm)

Using the above tables and your system manual, you should be able to figure out which kind of drive you have now and the appropriate upgrade path. The information below can help narrow down the choices for you.

In the smaller capacities (128GB and under), the M.2 SATA 2242 is more common. In larger capacities, due to the additional surface area needed to fit more NAND chips, the M.2 SATA 2280 or M.2 PCIe x4 2280 drives are the norm. We've not yet seen a PCIe x2 M.2 drive in the wild as yet, except for Plextor M6e. However, this drive sells with an included PCIe adapter card to allow installation into a standard PCIe socket in a desktop PC (update 20/5/14 - 'bare' M6e M.2 SSD's expected to be available for sale in 3-4 weeks time). In theory, you could remove the M.2 SSD from the adapter card, but this would void your warranty from Plextor.

The picture below shows the edge connectors of two different types of currently available M.2 SSD Drives.

 

The one on the left is the Samsung XP941. It has a single 'M' key and is PCIe x4 based. The one on the right with two notches has both an 'M' key and a 'B' key and is SATA based (like the MyDigitalSSD SC2 or the Crucial M500 M.2).

Check the card length

Before purchasing an M.2 SSD, you should also check the length of the existing drive, as not all are created equal. TheMyDigitalSSD SC2 128GB M.2 SATA SSD is a '2242' drive, so it's 22mm wide, and 42mm long. That's the maximum length that M.2-capable motherboards like the ASUS Maximus Extreme VI can handle, and it fits a lot of laptops/netbooks as well. SATA based M.2 drives can also be installed in any desktop machine with a free PCIe slot (and a spare SATA port on the motherboard) using a SATA M.2 to PCIe adapter.

The Samsung XP941 PCIe M.2 SSD, apart from being PCIe x4 based, is a '2280' drive, so it's 22mm wide, but 80mm long. Currently it's only supported natively (and bootable) in a few different laptop models, as well as a growing number of Z97 and X99 chipset based motherboards (the first being the ASRock Z97 Extreme 6 motherboard), all 2006-2012 model Mac Pro towers, or you can install it in any desktop with a free PCIe slot using a PCIe M.2 to standard PCIe adapter (there is limited support for booting windows desktops using the PCIe adapter currently, but it works in all Mac Pro models).

M.2 SSD Compatible systems and motherboards

The following is a list of some of the most popular M.2 compatible models being used today. Please add your questions and comments at the bottom of the page and help us grow and maintain this list.


PCIe 80mm M.2 NGFF compatible systems (2280)

  • Sony Vaio Pro 13 (requires PCIe x4 M.2 - Samsung XP941, and is bootable)
  • 2006-2012 model Mac Pro Tower (only confirmed tested with the Samsung XP941, requires a PCIe M.2 to standard PCIe adapter, OSX Leopard or higher, and is bootable).  Also compatible and bootable with Plextor M6e (which is an M.2 SSD, but permanently fixed to a standard PCIe adapter).
  • HP Zbook 17 G2.  Can be upgraded with the Samsung XP941 as confirmed by this Amazon review
  • Lenovo Carbon X1 G3.  Uses the new Samsung SM951, which is very much like the XP941, only PCIe 3.0.    This machine also works with the XP941.
  • HP EliteDesk 800 Desktop Mini G1 - tested and booting the XP941
  • Clevo P650SE - tested and booting 
  • Intel NUC NUC5i5RYK (works and boots with XP941)
  • Asus G771 (works and boots with XP941)

PCIe 80mm M.2 NGFF compatible motherboards (2280)

  • Note, all below motherboards and others with a free PCIe 2.0 x2 or higher slot will work and boot with both thePlextor M6e PCIe SSD (which is an M.2 SSD permanently fixed to a standard PCIe adapter) or the Mushkin Scorpion Deluxe PCIe SSD.
  • ASRock AMD Fatal1ty 990FX Killer Motherboard (supports PCIe 2.0 x2 / SATA M.2 and will work with theSamsung XP941 x4 SSD, but doesn't boot.)
  • ASRock X99 Extreme6 and Deluxe
  • ASRock Z97 Extreme6 (compatible with XP941 14/5/14, and boots)
  • ASRock X99 Extreme 4 (bootable with XP941 according to an ASRock rep)
  • ASRock X99m Killer Micro ATX. Fully supports XP941 according to this happy forum user.
  • ASUS H97M-E Motherboard.  Confirmed bootable with the Samsung XP941.  Thanks to 'Tatarik' for confirming this.
  • ASUS Maximus VI Impact Motherboard (supports PCIe 2.0 x1 / SATA M.2 - NO XP941) ***
  • ASUS Maximus VII Gene Motherboard (M.2 socket disabled if a PCIe 2.0 x4 device is installed.  Only 2-lane PCIe.  Will boot and run XP941)
  • ASUS Maximus VII Hero Motherboard (update 5/6/14 - At Computex 2014 in Taiwan,  I spoke with ASUS representatives who said that all Z97 chipset motherboards with the dual PCIe/SATA-based M.2 socket will boot the Samsung XP941, but because the socket is only 2-lane, will max out at about 800MB/s.)
  • ASUS Maximus VII Impact.  Reported on this forum post to be compatible and bootable with the Samsung XP941.
  • ASUS Maximus VII Ranger Z97 Motherboard.  Reported by one of our customers to be bootable with the Samsung XP941 when installed in the Lycom DT-120 adapter.  Requirements are to disable CSM and load intel raid drivers during the Windows installation.
  • ASUS Z97 Deluxe Motherboard (see notes in the ASUS document here regarding booting the XP941 and other PCIe M.2 SSD's, and the excellent instructions here.)  
  • ASUS Z97 Pro Motherboard.  The XP941 will boot in this motherboard in UEFI mode.  Whilst ASUS is working on a BIOS patch to support legacy booting with the XP941, see the ASUS document and instructions above for the Z97 Deluxe for more information.  Note, it seems the storage configuration settings relating to M.2 need to be set specifically to [M.2] and not just to [AUTO], in order to be able to boot the Samsung XP941.
  • ASUS X99 Rampage V Extreme.  This beastly motherboard fully supports the XP941 and allows 2x GPU's to run in SLI mode as well.  See this forum post for details.  Note, it seems the storage configuration settings relating to M.2 need to be set specifically to [M.2] and not just to [AUTO] to boot the Samsung XP941.
  • EVGA X99 Classic and Micro model motherboards.  Note, to install the XP941, you need to set the bios to UEFI boot rather than legacy.
  • Gigabyte GA-Z97-D3H Motherboard.  Samsung XP941 is bootable with these settings.
  • Gigabyte Z97X-UD5H Motherboard (supports PCIe 2.0 x2, no data available yet on XP941 compatibility.  
  • MSI Z97 Gaming 7 Motherboard (has dual SATA/PCIe M.2 socket.  No data available yet on compatibility of XP941 as of 20/5/14. 
  • MSI Z97 XPower AC Motherboard (has dual SATA/PCIe M.2 socket.  Unknown if XP941 works.)
  • MSI X99 motherboards.  Update 22/9/14: Some users report the XP941 can boot in this board with the latest beta bios and by disabling XMP settings.  See this forum post for more details.
  • Other motherboards with a free PCIe slot using a M.2 to PCIe adapter will work with the Samsung XP941 (not usually bootable, but can use the drive as additional high speed storage).  Most above motherboards and others with a free PCIe 2.0 x2 or higher slot will work and boot with both the Plextor M6e PCIe SSD (which is an M.2 SSD permanently fixed to a standard PCIe adapter) or the Mushkin Scorpion Deluxe PCIe SSD.

SATA 80mm M.2 NGFF compatible systems (2280)

  • Samsung ATIV 9 Plus Ultrabook (e.g. model NP940X3G, NP930X5J)
  • Lenovo ThinkPad X1 Carbon Gen 2 (new model released early 2014)
  • Razer Blade 14 (2014 model)
  • MSI GS60 Ghost Pro 3K and the GS70 Stealth Pro
  • Sony Vaio Pro 11
  • HP Folio 1040 G1

SATA 80mm M.2 NGFF compatible motherboards (2280)

  • ASUS Maximus VI Impact Motherboard (has a dual PCIe 2.0 x1 M.2 / SATA M.2 socket)
  • Other motherboards with a free PCIe slot using a SATA M.2 to PCIe adapter (Bootable)

SATA 60mm M.2 NGFF compatible systems (2260)

  • ASUS Zenbook Touch UX31LA
  • SONY Vaio Flip 13

SATA 42mm M.2 NGFF compatible systems (2242)

  • Acer Chromebook: C720
  • ASUS ROG: G750JH, G750JX
  • HP Chromebook 14
  • HP EliteBook: 820 G1, 840 G1, 850 G1
  • HP ProBook: 430 G1, 640 G1, 650 G1
  • Lenovo: G410, G510, G710, V4400u
  • Lenovo IdeaPad: L440, L540, U330, U430, Y410p, Y510p*
  • Lenovo ThinkPad: E431, E531, S531, S540, T431s, T440P, T440s, T540, T540p, W540, X240
  • Lenovo ThinkPad Edge: E531, E540
  • Lenovo ThinkPad Yoga
  • SONY VAIO PRO 13 Series **
  • SONY VAIO DUO 13 Series

* Some Lenovo IdeaPad models may ship without an M.2 connector, please check that your device has an M.2 connection before placing your order.

** Check your existing M.2 drive in the Sony Vaio Pro. If it's a Samsung XP941 model, then you have a PCIe based M.2 drive. See the picture at the top of the page for further information about PCIe vs SATA based M.2 SSD's.

*** This system supports only a PCIe x2 M.2 SSD, and likely will not work with a PCIe x4 M.2 SSD. It definitely doesn't work with the Samsung XP941.


SATA 42mm M.2 NGFF compatible PC Motherboards (2242)

  • Asus Maximus Extreme VI (use to create a Hybrid-SSD-like cache for an existing drive or RAID array using Intel Smart Response Technology (SRT))
  • Asus Maximus VI Formula
  • ASUS Maximus VI Impact Motherboard (has a dual PCIe 2.0 / SATA M.2 socket)
  • ASRock AMD Fatal1ty 990FX Motherboard (has dual function SATA/PCie M.2 slots)
  • Any other motherboard with a free PCIe slot using an M.2 to PCIe adapter