How to Add More M.2 SSD Slots?

Those who have tried the remarkable performance gains they can achieve with an SSD just can’t get enough of it. Hence, often people ask, how to add more M.2 SSD slots or how to add a second SSD if their motherboard only comes with a single M.2 slot.

Fortunately, the process of adding more M.2 slots to your SSD is fairly simple. It will require a small investment though. Basically, you need to purchase an M.2 slot PCIe expansion card. 

These PCIe expansion cards can be found featuring anywhere between 1-4 M.2 slots for NVMe SSDs.

However, before you go about making the purchase, it is imperative that you understand how to purchase the right M.2 expansion card, where you would plug it in, and also learn about PCIe lanes and how they matter for M.2 slots.

A Brief on PCIe Lanes, Slots and M.2 Slots

So as alluded to earlier, in order to add more M.2 slots to your motherboard, you will need to purchase an M.2 PCIe expansion card. These cards basically require a free PCIe slot on your motherboard and occupy PCIe lanes.

Its ok if all this sounds too confusing to you, I will break this down for you here.

What are PCIe Slots?

PCIe slots are used to add expansion cards to your PC including graphics cards, WiFi cards and M.2 expansion cards etc.

These are fairly hard to miss as all motherboards have them.

how to tell if pcie slot is bad w
PCIe Slots. Note that the bottom x16 slot only connects to four PCIe lanes.

Now there are different sizes of the PCIe slots. All of these slots connect to PCIe lanes. 

For instance, x1 slot is the smallest PCIe slot. This slot connects to only a SINGLE PCIe lane. Hence it is intended for smaller and low demanding expansion cards. 

An x16 slot is the largest PCIe slot and it connects to 16 PCIe lanes ideally. However, in many cases, you can find a PCIe x16 slot with a physical size of a full x16 slot but in reality it would only be connected to four PCIe lanes – as you can see in the image above, the bottom PCIe slot only connects to FOUR PCIe lanes.

It is recommended that you check with your motherboard’s specsheet to figure out the specs of each PCIe slot on your motherboard.

What are PCIe Lanes?

PCIe lanes are basically information highways that send information to and from the device and the CPU/motherboard.

There are a limited amount of PCIe lanes available to your PC and the total amount of PCIe lanes is determined by the CPU and the motherboard you have.

Also Read:

How Many PCIe Lanes Does an M.2 Slot Use?

Now this part is very important to understand.

An NVMe SSD operates on the PCIe interface. Hence, NVMe SSDs are also called PCIe SSDs. 

A typical NVMe SSD requires 4 PCIe lanes to work. Let me reiterate this point:

A PCIe NVMe SSD requires 4 PCIe lanes to work at optimal capacity.

This information will come in handy when purchasing the right M.2 PCIe expansion card.

You also have to understand that there are two types of M.2 SSDs. M.2 is basically the name of the form factor that the SSDs use. So there are M.2 SATA SSDs and M.2 PCIe NVMe SSDs

samsung 980 pro
Samsung 980 Pro. M.2 PCIe 4.0 NVMe SSD
Samsung Evo 860 SATA SSD m.2
Samsung Evo 860 SATA SSD with M.2 form factor

An NVMe SSD is far superior as compared to a SATA SSD. A SATA SSD connects to the SATA interface and DOES NOT use the PCIe interface or PCIe lanes.

The maximum speed an M.2 SATA SSD can give is 560 MB/s. M.2 PCIe NVMe SSDs, on the other hand, can reach speeds of 6500 MB/s. 

Now it is worth noting that while an M.2 NVMe SSDs requires 4 x PCIe lanes to work at optimal speeds, SATA SSDs do not. And this difference between the two is something you will need to keep in mind when looking for the expansion cards.

How to Add More M.2 SSD Slots to Your Motherboard?

Motherboard often come with around 1 – 3 M.2 slots. The following table shows the typical amount of M.2 slots on LATEST motherboards with different sizes.

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

Older motherboards may feature fewer or perhaps may not feature an M.2 slot at all.

If you have run out of M.2 slots, then you will need to procure an M.2 expansion card.

There are generally three types of M.2 expansion cards that you can find:

  1. 4 x M.2 Slots for NVMe SSDs with x16 Connector
  2. 1 x M.2 Slot for NVMe SSD with x4 Connector
  3. 1 x NVMe + 1 x SATA M.2 Slots with x4 Connector

1. Quad M.2 Slots for NVMe SSDs with x16 Connector

How to Add More M.2 SSD Slots
ASUS Hyper M.2. x16 NVMe M.2 expansion card with Four M.2 Slots

These are the most expensive and robust expansion cards as they offer four M.2 slots for NVMe SSDs. They are often an overkill for an average user.

As such these cards occupy 16 PCIe lanes. Recall from earlier that each M.2 slot for NVMe SSD requires four PCIe lanes. Hence if you multiply 4 M.2 slots with 4 PCIe lanes you get 16 PCIe lanes.

As such, the ASUS Hyper M.2 card above has an x16 connector and would require a free x16 slot on your motherboard. It will require a true x16 slot that actually offers the full 16 lanes. This is usually the first x16 slot on the motherboard.

The rest of the x16 slots often offer only 4 PCIe lanes and hence this card would not be compatible with x16(x4) slots.

This card can be occupied with FOUR M.2 NVMe or M.2 SATA SSDs.

x16 slot pcie
An x16 slot

2. Single M.2 Slot for NVMe SSD with x4 Connector

Expansion Card for one M.2 NVMe Slot. Source: Rivo

These are the most common expansion cards. These cards add a single M.2 slot to your PC and they fit into an x4 slot. Hence, they have an x4 connector.

Note that, there are often no true x4 slots on a given motherboard. The x4 slots on motherboards have the physical size of an x16 slot. They are hence labelled as x16(x4).

3. Single NVMe + Single SATA M.2 Slots with x4 Connector

nvme plus sata m.2 expansion card
NVMe M.2 + SATA M.2 Expansion Card. Source: Godshark

These M.2 expansion cards are also fairly common. Basically, they give you one slot for M.2 NVMe slot and one M.2 slot for SATA M.2 SSDs.

The NVMe SSD utilizes the x4 lanes whereas for the SATA M.2 SSD there is a separate connector that would plug into the SATA slot on your motherboard via the SATA cable provided.

Other Types of M.2 Expansion

There is a wide variety of other types of expansion cards as well. However, as long as you understand PCIe lanes, and the difference between SATA and NVMe SSDs, you should be able to procure the right card for yourself.

Just make sure you have a free PCIe slot on your PC with the corresponding connector size of your expansion card and make sure it has sufficient PCIe lanes for your M.2 expansion card.

Read in detail: What is the difference between SATA and SSD and HDD and NVMe?

Version of the NVMe M.2 Slot Expansion Card – Very Important

It should be noted that there are different versions of the M.2 slots and the M.2 slot expansion cards.

Recall from earlier that M.2 NVMe SSDs use the PCIe interface. Now PCIe interface is an ever evolving interface. So much so that with each newer version, the transfer speed per PCIe lane doubles.

The most current version of the PCIe is 4.0. 

Simply put, NVMe SSDs conforming to the newer PCIe 4.0 are almost twice as fast compared to the NVMe SSDs conforming to the older PCIe 3.0.

PCIe 4.0 NVMe SSDs are commonly referred to as Gen 4 SSDs whereas the PCIe 3.0 NVMe SSDs are commonly referred to as Gen 3 SSDs.

samsung 980 pro
Samsung 980 Pro. A Gen 4 NVMe SSD
Samsung 970 pro
Samsung 970 Pro. A Gen 3 NVMe SSD.

Now in order to use a Gen 4 SSD, you need to make sure you have a Gen 4 M.2 slot as well. For that you will need a motherboard that conforms to PCIe version 4.0.

For instance, AMD X570 motherboards have the M.2 as well as the PCIe slots conforming to v4.0.

In order to  add MORE GEN 4 SSD Slots, you will need to get a GEN 4 expansion card.

Asus gen 4 expansion card
ASUS Hyper M.2 X16 PCIe 4.0 X4

You can find Gen 4 expansion cards featuring 1-4 NVMe M.2 slots.

Also Read:

FAQ

Can I Add 2 M.2 SSD Slot To Your PC?

You most certainly can. For that you need to have two M.2 slots built-into the motherboard or invest in an M.2 slot expansion card.

How Many M.2 Drives Can I Have?

The amount of M.2 drives you can have depends upon the total amount of M.2 slots on your motherboard as well as how many expansion cards you can install on your motherboard.

For instance if you have two M.2 slot built-in and you have two PCIe slots with 4 lanes x16(x4) slots, then you can add two more M.2 slots to your PC. Since each M.2 slot for NVMe SSD occupied four lanes.

Final Words

So the simple answer to the question “how to add more M.2 SSD slots?” is to get a PCIe expansion card for M.2 slots. 

However, there are many different kinds and version of expansion cards. In order to choose the right one you will need to have a good grasp of PCIe slots, their sizes, PCIe lanes, and the difference between NVMe and SATA SSDs.

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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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