The M.2 slot, pronounced “M dot two”, is a long, narrow expansion slot on a motherboard that connects various high-speed M.2-compatible expansion cards and devices. M.2 slots have become increasingly common in modern motherboards, particularly in laptops and desktops
Besides connecting SATA and PCIe (NVMe) M.2 SSDs, an M.2 slot can also accommodate M.2 Bluetooth cards, Wi-Fi cards, and an Ethernet adaptor. M.2 slots are more compact than traditional SATA or PCIe expansion slots, so they are suitable for smaller form factors.
But remember, before you go to the market or buy an M.2-compatible device online, ensure your motherboard supports M.2. You should also know the different types and variations of M.2 slots, along with the possible differences. So, keep reading this detailed guide to learn this!
Does My Motherboard Support M.2?
To know whether your motherboard supports M.2-compatible devices or has M.2 slots, you’ll need to go through your mobo’s specifications or physically inspect your motherboard. However, going through the specification and finding M.2 compatibility is much easier.
So, get your hands on the motherboard manual/documentation that comes with it. If you can’t find it, look online for your motherboard’s specifications. We have used Gigabyte X570 GAMING X motherboard in this example; you will use your motherboard’s exact name.
- Know the exact name of your motherboard.
- Enter your motherboard name in the search bar and press Enter. For example, we typed in Gigabyte X570 Gaming X motherboard.
- Click on the Specification. If you get a different result, simply click on the first result (typically from the official brand) and then look for the Specification section inside.
- Go to the Internal I/O Connectors and look for the term “M.2” in this section. For example, Gigabyte X570 Gaming X has two M.2 connectors/slots.
NOTE: To know the exact type/specifications of M.2 connectors, go to the Storage Interface sections. For example, the two M.2 slots on Gigabyte X570 Gaming X are M-key type, support both SATA and PCIe interfaces, and are PCIe 4.0 x4/x2 SSD-compatible.
So, if your motherboard is M.2-compatible, note down a few more specifications of the available M.2 slots. Use the Storage Interface section or other such section for this. Note down these:
- How many M.2 slots it has – Most motherboards usually have 2 to 3 M.2 slots.
- The type of M.2 slots it has — There are different keying types (M, B, B+M) and lengths (2242, 2260, 2280) for M.2 slots.
- The protocol it supports — Either PCIe (also called NVMe) or SATA. Some may support both interfaces.
Although now you know about the M.2 slot available on your motherboard, your research doesn’t end here. Do you know the differences between the types of M.2 slots? If not, read this guide until the end to better decide whatever you want to choose or do.
What Are Different Types Of M.2 Slots?
M.2 slots come in various variations primarily distinguished by their physical length/size, keying, and interface protocol, where each has different specifications.
In Terms Of Lengths
M.2 modules come in different lengths, usually denoted by a 3- or 4-digit number (e.g., 2242, 2260, 2280). These numbers represent the module’s dimensions in millimeters. The first two digits indicate the width, and the following two indicate the length.
- 2230: 22mm wide, 30mm long
- 2242: 22mm wide, 42mm long
- 2260: 22mm wide, 60mm long
- 2280: 22mm wide, 80mm long
- 22110: 22mm wide, 110mm long
Typically, an M.2 slot can accommodate modules in various form factors. Take the Gigabyte X570 Gaming X motherboard as an example; both M.2 slots on this motherboard can support 2242, 2260, 2280, and 22110 modules; it only lacks the support for 2230 modules
In Terms Of Keying
M.2 connectors/slots have different keying configurations, which are notches or key slots on the connector edge. The keying determines the type of devices that can be used with a particular M.2 slot. The keying is identified by a letter, such as B, M, or B+M.
The common key types are:
- B-Key: Typically used for SATA and PCIe x2 (two lanes) interfaces.
- M-Key: Usually used for PCIe x4 (four lanes) interfaces.
- B+M Key: Supports both B-Key and M-Key modules, making it more versatile.
In Terms Of Interface Protocols
M.2 slots support different interface protocols, and the two main interface protocols are:
- SATA (Serial ATA)
- PCIe (Peripheral Component Interconnect Express)
The SATA and PCIe are interfaces that connect various network adapters, graphics cards, storage devices, etc., to the motherboard. PCIe is a faster interface than SATA, so PCIe M.2 slots are meant to provide better data transfer speed than the SATA M.2 slots.
SATA M.2 Vs PCIe M.2: What Is The Difference?
SATA M.2 and PCIe M.2 are two different interface protocols used by M.2 solid-state drives (SSDs) and other M.2-compatible devices. SATA M.2 slots use a SATA interface, while PCIe slots use PCIe interfaces based on NVMe communication protocol.
|PCIe (also called NVMe protocol)
|6 Gbps (for SATA III)
|Varies (e.g., PCIe 3.0 x4: 32 Gbps, PCIe 4.0 x4: 64 Gbps)
|Typical Use Cases
|High-performance tasks (gaming, video editing)
How Do I Know If My M.2 Slot Is SATA Or NVMe?
To know whether the M.2 slot on your motherboard is SATA or NVMe (PCIe), review the motherboard’s specifications. Use the documentation/manual that comes within the mobo’s package or search your motherboard’s exact name online to find its specs.
Here are the steps to find your motherboard’s specifications online:
- Enter your motherboard’s exact name into the search bar and press Enter.
- Open the first result that pops up in the SERP. It is mostly the official brand’s website that usually ranks at the top.
- Go to the Specifications > Storage Interfaces.
- Look at the M.2 connectors’ specifications. Try to find the terms SATA/PCIe within the M.2 slots’ specification box.
For example, we followed the same procedure for the Gigabyte X570 Gaming X motherboard. We found that it has two M.2 connectors supporting the SATA and PCIe 3.0/4.0 x4/x2 interfaces. NOTE: NVMe is the protocol used for PCIe devices; both refer to the PCIe interface.
What Can I Connect To An M.2 Slot?
Most commonly, M.2 slots connect Solid-State Drives (SSDs); these storage devices can be SATA M.2- or PCIe M.2-based. However, other than connecting storage devices, M.2 slot on a motherboard can also be used to connect the following:
- Wi-Fi and Bluetooth Cards — Provide wireless network connectivity in laptops and small form factor systems.
- LTE/4G/5G Modems — Used to enable cellular connectivity in devices like laptops and certain desktop systems.
- NVMe (Non-Volatile Memory Express) Accelerators — Used to accelerate certain storage or processing tasks.
- M.2 to SATA Adapters — Allow the use of M.2 SATA SSDs in M.2 slots that might primarily support PCIe-based devices.
Which M.2 SSD Is Compatible With My Motherboard?
So, up to this point, you know how to find three aspects of the M.2 slots available on your motherboard: keying types (M, B, B+M), lengths (2242, 2260, 2280), and protocol (either PCIe (also called NVMe) or SATA). If so, determining compatible M.2 SSD is easy. Consider these:
Your motherboard’s M.2 slots can use SATA or PCIe interface; however, some motherboards may support both. Choose a SATA M.2 SSD for the SATA M.2 slot, PCIe/NVME M.2 SSD for PCIe M.2 slot. Go for any SSD type if M.2 slots are both SATA and PCIe.
M.2 slots can be B-keyed, M-keyed, or B+M-keyed. All you need is to find the keying on your motherboard’s M.2 slots and an SSD with the same keying. NOTE: Codes like “Key M”, “Key B, or “Key B+M” are clearly mentioned on the SSDs.
Check what form factor M.2 module your motherboard supports; it can be 2230, 2242, 2260, 2280, and/or 22110. Find an SSD that has the same length.
To determine if your motherboard supports M.2, consult the motherboard manual/documentation to see its specifications to find whether the M.2 slot is on the motherboard. If unavailable, search for your motherboard’s exact name online to find the specifications.
Once you find the specification, navigate to the Internal I/O Connectors section and look for the “M.2” term. You can clearly identify the number of M.2 slots along with their keying types (B, M, B+M), supported interface protocols (SATA or PCIe), and form factors.
Frequently Asked Questions
Is It Possible To Add Additional M.2 Slots On A Motherboard?
While there is no direct way to embed an extra M.2 slot, you can use a PCIe expansion card as a workaround. Simply install an M.2 SSD expansion card into an empty PCIe expansion slot to get multiple high-speed M.2 PCIe connectors, depending on the card.
Is There A Performance Difference Between PCIe 3.0 And PCIe 4.0 NVMe Slots?
Yes. PCIe 3.0 has a 1 GB/s per lane data transfer rate, while PCIe 4.0 provides 2 GB/s. So, while a typical x4 NVMe SSD connected to a PCIe 3.0 slot provides a theoretical bandwidth of 4 GB/s, the same x4 NVMe SSD on a PCIe 4.0 slot would reach about 8 GB/s.
What If A Motherboard Doesn’t Have M.2 Slot?
If a motherboard lacks an M.2 slot but has a PCIe slot, you can use a PCIe adapter card in such a case. These PCIe cards convert the available PCIe slot into an M.2 connector to let you install an M.2-compatible device.
NOTE: These cards do come in M.2×4 variety as well.