How Many M.2 Slots Do Motherboards Have?

SSDs are the new norm for storage these days. Whether you want a faster PC or are planning on building a new one from scratch, SSDs are the perfect ingredient for a better performance.

Now generally, a typical SSD requires an M.2 slot to plug into your PC. Compared to a SATA slot – the traditional slots used for hard drives – M.2 slots are rarer which begs the question, how many M.2 slots do motherboards have really?

The answer to that question highly depends upon what motherboard you have. You can have anywhere between 1 – 6 M.2 slots on a modern motherboard these days.

In the following text, I will talk about how many M.2 slots a motherboard typically has and also about some basics on how to check how many M.2 slots you have on your motherboard.

A Little Primer: SATA vs PCIe SSDs

For starters know that there are two interfaces that SSDs may use, SATA and PCIe.

SATA SSDs

SATA SSDs use the slower SATA interface. This is the same interface that the typical hard disk drives use, as such the maximum transfer speed of a SATA SSD is 550 MB/s.

There are two types of SSDs: 2.5″ SATA SSDs and M.2 SATA SSDs.

SATA SSD Connectors power data
2.5″ SATA SSDs 

2.5″ SATA SSDs DO NOT require an M.2 slot. They use the typical SATA data and SATA power ports as found on a typical hard disk drive.

M.2 SATA SSDs, on the other hand, require an M.2 slot with SATA support. These look like your typical M.2 sticks:

What are SATA Ports Used For
Samsung Evo 860 SATA SSD with M.2 form factor with B+M Key.

M.2 PCIe/NVMe SSD

These are the wonder SSDs that you should aim for. Most of the modern systems feature these SSDs and if you are planning on making an upgrade, M.2 PCIe SSDs, aka NVMe SSDs, is what you should aim for.

samsung 980 pro
Samsung 980 Pro. PCIe 4.0 NVMe SSD with M Key.

Depending upon what version they conform to, you can have speeds of 3500 MB/s on Gen 3 NVMe SSDs and a speed of 5500 MB/s on Gen 4 NVMe SSDs.

Also Read: How to Use Two M.2 SSD?

So How Many M.2 Slots Do Motherboards Have?

Well, the answer to that question depends upon what type of motherboard you have.

The amount of M.2 slots a motherboard has largely depends upon its chipset and the CPU installed on it. Specifically, it depends upon the amount of PCIe lanes the motherboard chipset and the CPU attached to it offers.

For installing an NVMe SSD on an M.2 slot, the slot needs to have 4 x PCIe lanes.

As such, the more PCIe lanes a system has, the more M.2 slots it can offer!

The following table explains how many PCIe lanes different motherboard chipsets have:

ManufacturerChipsetPCIe LanesCategory
IntelZ69028
- 12 x v4.0
- 16 x v3.0
High Performance
H67024
- 12 x v4.0
- 12 x v3.0
High Performance
(Minus overclocking Support)
B66014
- 6 x v4.0
- 8 x v3.0
Mid Range
H61012
- 12 x v3.0
Budget
Z59024High Performance
Z49024High Performance
B46016Mid Range /
Mainstream
B56012Mid Range /
Mainstream
X29924Workstation
H5104Budget
AMDX57016High Performance
B55010Mid Range
A5206Budget
TRX4016Workstation
  • For Intel chipsets, not all PCIe lanes mentioned above are user accessible some are reserved for the built in systems.

Again, the lanes shown above are just the chipset lanes, you have to add the CPU lanes as well in order to tally the total amount of PCIe lanes a system has.

Newer Gen Intel and AMD CPUs have 20 PCIe lanes. Older CPUs may offer 16 PCIe lanes.

As such, if you have an older motherboard, you may notice caveats stating that a certain M.2 slot will NOT work unless you have a newer gen CPUs.

For instance, the following is an excerpt from the technical specs for the ASUS Z590A Prime motherboard.

ASUS Primze Z590 SSD NVMe PCIe 11th gen
One of the M.2 slots requires 11th Gen CPU. Source: ASUS

This motherboard has 3 x M.2 slots. However, one of them will ONLY work if you have an 11th Gen Intel CPU. Why? Because 10th and older gen Intel CPUs have 16 PCIe lanes. 11th Gen and newer have 20 PCIe lanes.

The first M.2 slot is connected to the 4 PCIe lanes of the CPU which only the 11th or the newer Gen GPUs have.

Form Factor also Matters for M.2 Slot Count

motherboard form factor comparison
Comparing different motherboard form factors. Source: Wikimedia.

The smaller the motherboard, the fewer the M.2 slots it would typically have.

Form Factor No. of M.2 Slots (Range) Typical Number of M.2 Slots
EATX 5-6 5
ATX 2-5 3
Micro ATX 1-3 2
Mini ITX 1-2 2

EATX motherboards, of course being the workstation motherboards, have the highest amount of M.2 slots.

ATX, Micro ATX and Mini ITX TYPICALLY have 2, 2, and 3 slots respectively.

I have taken into consideration only the newer chipsets here from the AMD 500 and the Intel 400, 500 and 600 series.

Also Read: Are All Motherboards the Same Size?

Typical Number of M.2 Slots Found on Different Motherboard Chipsets

The table in this section below shows all the newer motherboard chipsets and the amount of M.2 slots you can find on motherboards featuring the respective chipset.

A bit of a primer on the motherboard chipset though, both AMD and Intel have different chipsets for commercial motherboards.

AMD has the A, B and X series:

  • A series, such as the A520, is found on budget motherboards
  • B series, such as the B550, is found on mid range motherboards
  • X series, such as X570, is found on the high end motherboards

Intel has the H, B and Z series; H is further divided into two chipset series such that:

  • H*10, such as the H610, is for budget builds
  • B*60, such as the B660, is for mid range builds
  • H*70, such as the H670, is for high end builds WITHOUT overclocking support.
  • Z*90, such as the Z690, is for premium builds WITH overclocking support. 

Note “*” asterisk sign marks the generation.

As such, the more premium a chipset your motherboard has the higher are the chances of it featuring a higher number of M.2 slots.

This table explains it further and should give you an idea about how many M.2 slots to expect for a given chipset.

MakeChipsetNo. of M.2 Slots (Range)Typical Number of M.2 Slots
IntelZ6902-54
H6702-43
B6601-32
H6101-21
AMDX5701-62 -3
B5501-42
A5201-21
  • Note the samples were taken from the newer Intel 600 and AMD 500 series chipsets.

Intel Z and AMD X series naturally have the highest number of M.2 slots both typically and with respect to the maximum number. Typically they can have 3 x M.2 slots on an ATX form factor and on the high end models, they can offer 5-6 M.2 slots as well.

Other than the chipset and the motherboard size, there are many other factors that can contribute to how many m.2 slots do motherboard have.

For instance, if a motherboard features a higher number of PCIe expansion slots, then that can result in a reduced number of M.2 slots since the system has a limited amount of PCIe lanes.

Other than knowing how many M.2 slots you have, you also have to consider whether a certain SSD will be compatible with your motherboard or not.

I recommend reading this article: How to Check SSD Compatibility?

FAQ

How Many M.2 Slots Do I Have?

To check how many M.2 slots you have, you can:

  1. Check physically on the motherboard
  2. Read the specifications

A typical M.2 slots looks like this:

M.2 Slot Length
A typical M.2 slot with the different length marked. The holes at different length interval are where you would screw in your SSD. Source: rog.asus.com

Reading the specification of your motherboard is the best and the most definitive way to figure out how many M.2 slots it has including its type and the SSD type and generation they  support, i.e SATA SSD, Gen 3 NVMe, Gen 4 NVMe etc.

how many M.2 slots do motherboards have
M.2 slots on MSI MEG B550 Unify. This motherboard has 4 x M.2 slots. Source: MSI

Also Read: How to Tell if My M.2 Slot is NVMe or SATA?

How Many M.2 Slots Can I Use?

You can use as many M.2 slots as your motherboard has available.

However, again, you must refer to the specifications to check if there are any caveats with certain M.2 slots. 

For instance here:

ASUS Primze Z590 SSD NVMe PCIe 11th gen

One of the M.2 slots can ONLY be worked if you have an Intel 11th Gen CPU installed.

Do Motherboards Have Multiple M.2 Slots?

Majority of the newer motherboards have multiple M.2 slots.

Older and budget friendly motherboards may have one M.2 slot only.

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Author:

Atif Qazi
Atif Qazi is the founder of PCGuide101. He is a digital nomad who loves everything PC. He is a PC builder, tech enthusiast, engineer, and a lover of single player lore-rich RPG games.

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