M.2 and NVMe SSDs are more popular than ever in the PC hardware space, but what are they, and how do they actually impact your experience?
Today, I’m going to cover those questions and more as we dive into all you need to know about M.2 and NVMe SSDs.
What Are M.2 and NVMe SSDs?
What is an SSD?
First, let’s take a moment to define what an SSD is and how it functions.
An SSD, or Solid State Drive, is a high-performance storage drive without any moving parts. (The lack of moving parts is what makes it “solid state”.)
Until the debut of M.2 SSDs, SSDs were instead released in a 2.5-inch drive format, just like 2.5-inch HDDs made primarily for laptops.
They also used the same SATA connector and bandwidth- more on that in a little bit.
For now, it’s important to understand the basics of an SSD as a high-performance alternative to HDDs with no moving parts.
So, what makes an SSD M.2?
What is an M.2 SSD?
The M.2 in M.2 SSD refers to a form factor.
The M.2 form factor comes in a few varieties, but the most popular by far is the M.2 2280 standard.
“22” is a measurement of the drive’s width in millimeters (mm), and “80” is a measurement of the drive’s length, also in mm.
If you don’t have a ruler on hand, that’s about the size of a USB thumb drive, except M.2 drives are also extremely thin.
An M.2 SSD in and of itself isn’t necessarily better than a “standard” SATA SSD besides being so much smaller.
In fact, many M.2 SSDs are still SATA SSDs at heart. Not all of them are, though- that’s when we start getting into NVMe SSDs.
What is an NVMe SSD?
An NVMe SSD is an M.2 SSD that uses the NVMe (Non-Volatile Memory Express) standard.
With NVMe SSDs, the SSD uses PCI Express bandwidth rather than SATA bandwidth, allowing for significantly faster read and write speeds to be reached.
As generations of PCI Express are released with bandwidth improvements, NVMe SSDs follow suit- at the time of writing, there are matching NVMe SSDs for both PCI Express Gen 3 and PCI Express Gen 4 motherboards.
Are all M.2 SSDs NVMe?
No, many M.2 SSDs are instead reliant on SATA bandwidth.
This makes them M.2 SATA SSDs.
What is a SATA SSD?
Traditionally, a SATA SSD is an SSD that comes in a 2.5-inch drive enclosure and uses a traditional SATA cable and connector on the motherboard, as well as a power cable.
However, M.2 SATA SSDs that run at the same speeds are also available, albeit in a smaller form factor, and require different connectors than 2,5″ SATA SSDs.
Since they’re M.2, they’re also plug and play, not requiring extra power or SATA cables to operate.
How Fast Are M.2 and NVMe SSDs?
How Fast is an M.2 SATA SSD?
An M.2 SATA SSD is just as fast as a regular SATA SSD- that is, maxing out at around 550 MB/s in sequential read and write speeds, give or take a couple of dozen MB/s in either direction.
Of course, slower models of SSD exist as well, and certain manufacturing processes can even introduce slower-than-usual speeds in certain workloads.
The overall ~550 MB/s range limiter is imposed by the SATA 3 standard, which was primarily created for use with desktop hard drives.
Desktop hard drives or HDDs (Hard Disk Drives) are composed of spinning disks, thus their speed is limited by RPM (Rotations Per Minute).
While you can still get decently fast HDDs, even most entry-level SSDs outclass them in raw speed.
The limitations of the SATA storage standard is exactly why SSD manufacturers introduced the faster NVMe standard to the market.
How Fast is an M.2 NVMe SSD?
Well, the answer actually depends on your particular model of NVMe SSD, even more so than with SATA SSDs.
NVMe directly utilizes a PC’s PCI Express bandwidth and lanes- the same part reserved for high-speed expansion cards.
This allows for minimum speeds that start in the gigabytes per second.
As the motherboard and NVMe SSD’s generation increases (Gen 3 and Gen 4 being the current standards), higher speeds are also enabled.
Even within a particular generation of PCIe/NVMe, however, you can still see a lot of variability in performance.
The low end of PCIe Gen 3 still starts around 1 GB/s in read and write while the high-end peaks around ~3.5 GB/s.
Meanwhile, the low end of PCIe Gen 4 starts in that Gen 3 high-end, while Gen 4’s high end is still being pushed as high as 7 GB/s in sequential read and write.
Compared to the speeds of SATA SSDs and especially SATA HDDs, the latest NVMe SSDs have come quite a long way in raw read and write speeds.
But how do these astronomically higher numbers actually impact real-world performance?
How Does an NVMe SSD Improve Productivity Performance?
NVMe SSDs improve most forms of productivity.
Launch times for all applications are considerably decreased just by having an SSD.
However, NVMe SSDs don’t impact initial launch times quite as much as the initial upgrade to a SATA-tier SSD from an HDD.
Even though there is often an exponential increase in raw MB/s, there are other factors that go into operating system boot time. (For instance, you may also be CPU or RAM-bottlenecked.)
Also, since those high-end speeds are for sequential read and write only, loading applications or an OS will be considerably slower. You might have 12x the speedup of an NVMe PCIe 4 M.2 SSD over a SATA SSD in sequential read / write speeds, but when you’re loading thousands of small files that are scattered randomly across your storage, performance tanks big time. An NVMe SSD in random read / write workloads is only about 2 – 3x as fast as a SATA SSD.
In addition to being generally more performant than a standard drive, an NVMe SSD also serves as an asset whenever your paging file needs to be used.
A paging file (or similar app-specific cache) is when you’ve run out of physical memory for the task you’re trying to do, so your disk storage is used as a backup.
With an HDD or slower flash storage, this can result in a significant performance drop.
With an NVMe SSD, especially particularly fast ones, you can mitigate the performance drop caused by tapping into a fast disk-based cache in any application (sort of an extension of your RAM).
This is because an NVMe SSD is massively faster than the slow storage that paging files were originally made for, allowing better performance to be achieved than would have been possible on a mechanical hard drive or cheap flash storage.
For accelerating regular desktop use and high-end multitasking, an NVMe SSD is a great fit.
How Does an NVMe SSD Improve Rendering Performance?
When it comes to things like rendering and editing video projects and 3D scenes, does an NVMe SSD improve rendering performance?
In some cases, yes.
Let’s start with the video projects example, as that’s the easiest to explain.
While it’s true that your standard desktop hard drive has more than enough speed to watch a single 4K stream, editing that streamed content at its original resolution and file sizes isn’t quite viable.
You need a speedy SSD in order to work through a lot of high-resolution, potentially uncompressed, high-bit-depth, footage in an editing timeline that has multiple footage layers without experiencing noticeable hitches.
The same applies to heavy-duty video encoding and transcoding.
When you start thinking about how large video files can be (think 1-2+GB/min)- especially when uncompressed or at particularly high resolutions- it becomes clear how the Gigabytes per second of read speeds offered by NVMe comes in handy for managing multiple in real-time.
Your heavy-duty rendering applications tend to have disk-based memory caches of their own that are also accelerated by an NVMe SSD compared to an HDD, but this is the same for pretty much any application on the system through the paging file.
For 3D rendering, NVMe SSDs are also great for more quickly loading high-quality assets such as high-res textures, high-poly models, particle / physics / simulation caches from disk, etc.
Depending on the Render Engine you’re using, your scene might generate so much data at rendertime that it spills over your VRAM (If you’re doing GPU rendering) and RAM into your paging file. At that point, having a fast NVMe will make a huge difference.
Writing your finished frames in an uncompressed multi-layered EXRs Format to disk too is something that’ll need fast write speeds that an NVMe SSD can help with.
Chances are you’ll be doing some post-production, compositing and editing after you’ve rendered your image sequences, and those kinds of workloads are heavily dependent on fast storage performance.
How Does an NVMe SSD Improve Gaming Performance?
Last but not least, how does an NVMe SSD actually impact your gaming performance?
It’s worth noting that the latest consoles (PlayStation 5 and Xbox Series S/X) at the time of writing are shipping with NVMe Gen 4-grade SSDs out of the box.
In the PS5’s case, you’re even required to make sure that any replacement NVMe drive meets that Gen 4 requirement, as well as a suggested minimum speed of 5.5 GB/s.
However, when actually tested by Digital Foundry, it was found that one of the PS5 games that made the most use of NVMe (Ratchet and Clank) still worked perfectly fine with a mere 3.2 GB/s drive.
So even for a game that is explicitly built around an NVMe SSD, you don’t necessarily need to push the highest possible speeds enabled by Gen 4- at least not yet.
Outside of this more console-centric use case and in the wider PC gaming space, an NVMe SSD will noticeably improve your in-game load times.
Compared to a SATA SSD the differences may seem marginal but will be more noticeable in games with larger filesizes.
CPU speed also plays a direct factor in how fast you can load your game off of a storage drive, too.
Besides improving in-game load times, an NVMe SSD may also improve on instances of pop-in or slow texture/model load-in.
This doesn’t usually impact in-game performance but can definitely have an impact on visual quality, especially in open-world or large-scale multiplayer games.
Ultimately, an NVMe SSD is unlikely to impact in-game FPS outside of extreme niche cases.
Unless the game specifically requires NVMe-tier speeds, which isn’t really a thing on PC yet, you aren’t going to notice performance changes from NVMe compared to a SATA drive.
Reasons To Still Consider M.2 SATA SSDs
Performance Is Still Comparable to NVMe in Many Scenarios
M.2 SATA SSDs have much lower listed frequencies than NVMe SSDs, yet can turn around similar performance in quite a few scenarios.
This doesn’t mean that NVMe drives don’t have their benefits- they’ve been discussed pretty extensively above- but that games and applications still have to be built to properly utilize them.
This is no different than any other piece of software being more CPU or GPU-reliant.
Since SATA-based M.2 drives are still technically worse, they’re generally a lot cheaper than their NVMe counterparts.
This makes them competitive with both cheaper and more expensive storage hardware, with some snatched up for secondary rather than primary storage.
I myself use a mixed NVMe M.2 and 2.5-inch SATA SSD configuration.
I’ve kept all of my largest games and video files on the NVMe drive in order to maximize its higher speeds, whereas my OS and programs can be run off the SATA SSD with a little noticeable delay.
My PC still boots and updates in seconds.
Are There Any Workloads That Require NVMe SSDs?
So, what workloads actively require NVMe SSDs?
As focused on above, NVMe SSDs most often come into play where you’re regularly needing to pull and manage dozens of gigabytes from storage.
Stuff like 3D rendering, file compression, and video rendering all benefit from an NVMe SSD compared to a SATA SSD.
Nothing really requires an NVMe SSD outside of a few video games, though.
At the time of writing, the main example that comes to mind is Ratchet and Clank: Rift Apart for PlayStation 5, but as covered by Digital Foundry, even that game doesn’t make full use of the PCIe 4.0 minimum standard required for PS5 NVMe upgrades.
At the end of the day, most workloads today don’t require NVMe…but if you use one of the ones that do, especially as a professional, they remain highly recommended.
What Are The Best NVMe SSDs?
So if you need or just want an NVMe SSD, what are the best ones for you to start with?
Besides the general recommendation that you shop in accordance with your motherboard, laptop, or console’s desired SSD spec, you’ll want to aim for a good balance between pricing and performance.
I think I’ve rounded up a pretty good selection of the best NVMe SSDs available on the market in another of my articles– I’ll be sure to keep it updated moving into 2022.
How Many M.2 SSDs Can You Have?
In short: you can have as many M.2 SSDs as you have M.2 slots.
However, SATA M.2 slots and NVMe M.2 slots are not cross-compatible.
Additionally, even if you have both present in your system, you may want to be careful to avoid certain RAID configurations that could slow down the faster NVMe drive.
To learn more about how many SSDs you can have in a system, not just M.2 SSDs, consider reading the detailed guide we wrote on the topic.
Over to You
And that’s it, at least for now!
I hope that this article helped you come to a better understanding of how M.2 and NVMe SSDs work and actually impact your end-user experience.