M.2 NVMe SSDs: Two or More Affect Performance?

Here’s how having two or more M.2 NVMe SSDs affect your computer’s performance:

Installing M.2 NVMe SSDs definitely impacts the performance of the computer. 

If you are upgrading from slower drives, then things will run considerably faster. 

If you’re adding drives, then eventually, too many M.2 drives can hog resources and slow down the general performance of the computer.

So if you want to learn all about how your computer’s performance is affected by two or more M.2 NVMe SSDs, then this article is for you.

Let’s get started!

M.2 NVMe SSDs: Two or More Affect Performance?

How Do Storage Drives Affect Performance in General? (3 Points)

There are two primary concepts to consider. 

How does installing a bunch of M.2 drives impact the rest of the computer? 

Also, how does the choice of drive impact the computer?

We’ll go over all of it, but the easy starting point is to talk about the drives themselves. 

Whatever you choose as the main storage drive, it has an impact on performance. 

The speed of the drive, how it is installed, and how you manage your own data all matter.

#1 Drive Speeds

To understand what is happening with M.2 drives, it’s important to understand more about the different drives available for a computer. 

For the most part, there are three different types of storage technology that a computer can use to hold the operating system and all other stored data.

(Technically there are more options, but these three constitute the vast majority of computer drives.)

The three design options are HDDsSSDs, and NVMe drives. 

Let’s break down each one.

An HDD is a hard disk drive.

This is a drive that has a circular disk that holds information using magnets.

It spins in circles very fast, and the speed at which the disc can rotate largely impacts how fast the drive can store or retrieve data. 

These are the slowest of the primary drives, and modern computers typically don’t use them for primary storage anymore. 

Instead, a lot of computers use them as backup drives and for additional storage because they cost a lot less than the other types of drives.

SSDs are solid-state drives.

These are drives that have no moving parts. 

Instead, electric currents are used to store and retrieve information, and the process is substantially faster than the older method of spinning a platter. 

You’ll see these types of drives in a lot of budget-oriented computers. 

They’re also common for backups and extra storage because they’re faster than HDDs and less expensive than NVMe drives.

NVMe drives are nonvolatile memory express drives. 

Technically speaking, they are a different type of solid-state drive. 

There are no moving parts with an NVMe drive, but this design uses faster data management methods than the older SSD designs. 

Arguably more important is that NVMe drives are designed to use PCI lanes (typically PCIe). 

We’ll get into PCI lanes more later, but here’s the gist. 

By connecting to the computer with PCI, an NVMe drive can talk to the other parts of the computer a lot faster.

So, you have three different types of drives. 

Does having two or more NVMe drives affect performance? 

Well, if the additional NVMe drives are replacing SSD or HDD drives, then this change will speed up performance.

If you’re just adding more drives, then there are things to consider.

#2 Primary vs. Secondary Drives

Every computer has a mainboard. 

They’re also called motherboards and logic boards.

This is the central component of the computer that connects all of the other pieces. 

So, the design of the mainboard is quite important.

It’s common for a mainboard to have a primary drive connection with any number of additional connection slots. 

Even when using M.2 drives, this is typically the case, and it matters.

The primary drive slot usually has better access to the primary components of the computer.

This can get rather complicated, so let’s keep it simple. 

The fastest route that data can take from an M.2 slot to the CPU is determined by the design of the circuits that connect them. 

Because of physics, there will be a location that is best for an M.2 slot, and this is reserved for the primary slot.

What does all of this mean?

Well, you want the applications that matter the most to run from the primary M.2 slot. 

Backup information and extra stuff that doesn’t have to perform as well can go on the drives in the additional slots.

In other words, it’s important to install your operating system on the primary drive. 

If you don’t, then this can lead to small drops in performance. 

The same goes for any applications that you use a lot and need to be fast. 

As an example, if you’re a professional video editor, then you should probably put your video editing software on the primary drive.

#3 Mixing and Matching Drive Types

As you have already learned, there are multiple types of drives that you can use to store information on your computer. 

If you use multiple drives, then it’s important to think about how they interact.

Let’s say you have two M.2 drives and three additional drives that are not NVMe. 

How you allocate these drives can impact performance. 

As already discussed, the operating system and most important applications should be installed on the primary M.2 drive.

Aside from that, there are nearly countless ways you can use the other drives to store things. 

You can set up the non-NVMe drives in a RAID configuration for really good backups. 

You can pick one drive for games, another for pictures, and another for movies.

When you’re thinking about all of these options, it’s important to remember the differences in speed across these drives. 

If the information being stored needs to be fast, put it on an NVMe drive. 

If it doesn’t matter (like pictures), then it can go on the slowest drive.

It’s up to you, but these decisions do have an impact on performance.

How Does Using Multiple PCI Slots Impact Performance?

So far, we’ve only really been looking at the drives themselves. 

When it comes to how NVMe drives impact performance, the PCI slots are arguably more important. 

We’ll get into the details, but here’s the zoomed-out idea. 

If you use a lot of PCI slots on your computer, it can slow things down.

What Is a PCI Slot?

I kind of brushed over this earlier, so let’s get into it now. 

First, PCI stands for peripheral component interconnect

That’s very fancy and technical, but really, this is a way that devices can talk to your computer. 

Each mainboard is different, but typically, there are multiple PCI slots available for any motherboard.

There are also different kinds of PCI slots, like mini PCI and PCIe. 

We don’t need to get into the specifics of all of these variations. 

Instead, we can reduce the concept down to a few important things. 

First, PCI slots provide the fastest communication currently available between computer components.

This is why all of the major pieces use some form of PCI connection. 

Your CPU, GPU, RAM, and potentially your storage drive all use this type of connection.

It’s clear why you would want to use hard drives that can connect via PCI since it’s clearly faster. 

But, how the computer uses PCI slots is important.

There are only so many slots on a given board, and splitting resources across them can get complicated.

Sharing PCI Lanes

Again, we’re going to keep this distilled down to the basics. 

Your mainboard has a limited number of PCI lanes available for use at any one time. 

Now, they aren’t all necessarily connected together. 

So, you can have a set of lanes that works with the RAM but isn’t connected to the NVMe drive.

There’s a lot of variation here.

But, for any PCI device, it is probably sharing lanes with at least something else on the board (assuming you’re using multiple PCI slots). 

How the lanes get shared is a big deal. 

If you max out your board and use every single PCI slot available, then lane sharing is definitely going to impact performance.

While your extra M.2 drives are active, they are taking up some of the lanes and the resources attached to those lanes. 

If they hog too many resources, it can slow down other components on the computer.

GPUs tend to show problems before anything else. 

GPUs handle graphics processing, so they deal with huge volumes of data.

They need open lanes in order to work at the highest speeds and volumes possible. 

If an M.2 drive is eating up some of those lanes, then the GPU can’t do as much, and you can get visual performance problems.

This is a pretty specific example, and it’s designed to highlight the general idea. 

Using a single M.2 drive is very unlikely to slow down your graphics card. 

Even using two NVMe drives probably won’t cause a problem. 

But, if you have a lot of slots, and you max everything out, then the odds of seeing visual slowdowns go up pretty quickly.

Also, this isn’t limited to the GPU. 

Any component that shares lanes can slow down when you overtax the computer. 

So, don’t install more M.2 drives than you need. 

Considering that they can hold a lot of information, most consumer users never need more than two drives anyway. 

If you really need that much storage, you can use SSD drives that aren’t on the PCI lanes.

You can even involve external drives. 

All of this will help you maximize performance while storing as much information as you want.


  • Theresa McDonough

    Tech entrepreneur and founder of Tech Medic, who has become a prominent advocate for the Right to Repair movement. She has testified before the US Federal Trade Commission and been featured on CBS Sunday Morning, helping influence change within the tech industry.

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