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If you have a spare M.2 NVMe SSD that you can’t find a new home for, a sensible solution is to put it in an external USB enclosure. That way, you can instantly reuse it for backups, network storage, another Steam library folder, or whatever else you can think of. With cost per GB inflating due to AI demand in 2026, making the most of the storage space you already own makes even more sense.
But what sort of enclosure? There are plenty of options for M.2 form-factor drives and they promise to do more or less the same thing (and with some exceptions, most of them do).
Choosing an M.2 Enclosure Based on Value & Functionality
The vast majority of NVMe enclosures use a USB 3.2 Gen 2 (10 Gbps) interface, in large part to retain compatibility with the traditional Type-A port, which maxes out at 10 Gbps. All faster enclosures require USB-C.
And almost regardless of the M.2 SSD used, any such enclosure should utilize all of its 10 Gbps bandwidth. The sole exception is if you use a SATA SSD in the M.2 form factor, which would be limited by its internal 6 Gbps interface. Although some enclosures support M.2 SATA drives, the drives themselves are rare, so most enclosure candidates are on PCI-Express 3.0 (Gen3) or better.
Since just about any budget NVMe drive can transfr data at rates exceeding 10 Gbps, this also raises the question of whether you should opt for a more capable external interface. If you have a USB 3.2 Gen 2×2 or USB4/Thunderbolt port, that will come closer to maxing out the SSD’s capabilities. There are of course such options on the market (we’ve tested one), but the performance benefits are questionable for must use cases (more on this later).
At this time, I would argue that 10 Gbps NVMe M.2 enclosures offer the best value for most users. They are also more versatile due to theUSB Type-A connector, which is compatible with just about any PC. Using an external SSD to move data from an older system without USB-C port, to a newer one, is a very common scenario.
Last update on 2026-01-20 / Affiliate links / Images from Amazon Product Advertising API
Best Affordable M.2 Enclosure? SSK SHE-C325 Pro
Among the most affordable NVMe USB enclosures we’ve tested, the SHE-C325 Pro from SSK stands out as a decent blend of functionality, style, and reasonable price. It matches the performance of any other USB 3.2 Gen 2 model, and it also comes with a thermal pad and rigid aluminum housing.
Last but not least, the box also contains dual USB cables (C-to-A and C-to-C), which adds convenience. Since it maxes out at 10 Gbps, it can also utilize the full bandwidth with its Type-A cable.
Some compromises are noticeable compared to slightly pricier models. All parts of the SSK enclosure, including the aluminum casing itself, are thinner and feel less rugged overall compared to its more expensive counterparts. It also uses a rather unconventional mechanism to lock the SSD in place, with a flexing PCB and plastic hooks.
This might become an issue if you swap SSDs around a lot, e.g. for cloning, but for permanent use it will do just fine.
Shopping links: Amazon, Newegg
Best Value: Ugreen SATA/NVMe Enclosure
The Ugreen SATA/NVMe M.2 enclosure comes in a very practical and robust design. It’s built like a tank and ships with a thick thermal pad as well as a protective rubber frame. Two cables with Type-A and Type-C connectors are also included in the box. Instead of a tool-free design (which often replace simple part for complex, fragile ones), the enclosure’s finned aluminum lid has a single screw, making it exceptionally easy to swap SSDs.
Like the SSK model, Ugreen’s case uses the same Realtek RTL9210B USB bridge, which supports both PCIe/NVMe and M.2 SATA SSDs. Of course, only a PCIe/NVMe drive will allow it to reach its maximum 10 Gbps sequential performance.
While it offers no surprises on the performance side, what makes the Ugreen enclosure attractive is an impeccable quality impression and easy operation. The only real downside to the abundance of aluminum is that it’s also a fair bit heavier than cheaper alternatives.
Shopping links: Amazon, Newegg
Premium RGB Enclosure: Asus Strix Arion
The RGB-equipped ROG Strix Arion is a premium PCIe enclosure that comes ready to shift colors along with your gaming rig using Asus’ Aura Sync software. Instead of a Realtek USB bridge, the Asus variant uses an ASMedia ASM2362 chip. The practical difference is no support for M.2 SATA SSDs, but that’s less of a problem for most users.
Asus highlights that the Strix Arion features ‘screwdriver-free’ installation. Instead, the manufacturer opted for a tool working like a SIM tray ejector pin. This works well enough but is not objectively better than using a screwdriver. The SSD is then secured using a thumbscrew (and/or a flathead screwdriver). Also, thick thermal pads are pre-mounted on the enclosure’s lid for a tight fit. As a result, the Arion runs quite cool despite being thinner than most competitors.
As previously noted, the performance of an M.2 PCIe/NVMe enclosure like the Asus is primarily constrained by the USB interface, meaning the Asus enclosure is no faster than any other 10 Gbps model. But the main selling point here is design – especially the Strix Owl RGB highlights. It’s also far more robust than cheaper enclosures.
Shopping links: Amazon, Newegg
M.2 SSD Enclosure Performance Benchmarks
The performance of an M.2 PCIe/NVMe enclosure shouldn’t surprise anyone, as it’s limited by the USB interface alone. In general, the sequential performance of a 10 Gbps USB 3.2 Gen 2 interface will be just under 1,100 MB/s, and you can roughly double that to just over 2,000 MB/s for USB 3.2 Gen 2×2.
To put these numbers in context, I have put the enclosures through some of the same tests and benchmarks that we use for testing internal SSDs. To eliminate any potential bottlenecks caused by the SSD, all enclosures are tested using a Samsung 990 Pro, a high-end PCIe Gen4 drive. However, the results are unlikely to look much different to any other PCIe SSD.
Sequential and Random Performance (CrystalDiskMark)
As evidenced by the CrystalDiskMark sequential performance chart, any M.2 enclosure will use all of the available bandwidth when connected to a sufficiently fast USB port. Incidentally, this also means that an external PCIe/NVMe SSD in a regular 10 Gbps enclosure is almost twice as fast as high-end internal SATA drives.
Random performance with small chunks of data is a better proxy for overall performance in a range of everyday tasks. It also evens things out a bit compared to mainstream internal M.2 SSDs. The USB interface is still a limiting factor, and a 20 Gbps enclosure remains much slower than, for example, the internal WD Black SN770. Interestingly, write performance is still better with the entry-level (internal) SATA drive but internal M.2 SSDs are practically always faster.
But how will an enclosure behave in a real-world-like gaming scenario? Load times in the FF XIV standalone benchmark are actually quite impressive, especially when compared to an internal hard drive. The 20 Gbps enclosure does offer some improvements here as well, reducing loading times by almost a second. However, this benchmark combines the total loading times for five levels, so it’s a barely noticeable difference.
Is a 20 Gbps (or Faster) Enclosure Worth It?
As mentioned, M.2 SSD enclosures with the 10 Gbps USB 3.2 Gen 2 interface and a Type-A connector are compatible with a wide range of PCs and laptops. USB 3.2 Gen 2×2 (20 Gbps) ports require Type-C connectors and are much less common, thus limiting the usage scenarios. Thunderbolt 3/4 or USB4 offers up to 40 Gbps of bandwidth, but even in 2026, these interfaces are still few and far between outside of MacBooks and high-end PC motherboards.
USB Bandwidth Chart
| USB 3.2 Gen 1(x1) | USB 3.2 Gen 1x2 | USB 3.2 Gen 2(x1) | USB 3.2 Gen 2x2 | Thunderbolt/ USB4 |
|
|---|---|---|---|---|---|
| Bandwidth | 5 Gbps | 10 Gbps | 10 Gbps | 20 Gbps | Up to 40Gbps |
| Formerly known as | USB 3.1 Gen 1 USB 3.0 | -- | USB 3.1 Gen 2 | -- | -- |
| Connector options | Type-A Type-C | Type-C only | Type-A Type-C | Type-C only | Type-C only |
Unlike Thunderbolt, USB is backward-compatible, so USB-based M.2 SSD enclosures can operate on slower interfaces but will be bandwidth-limited. Another limitation is that only Type-C-only cables are required at higher bandwidths than 10 Gbps.
Better Performance: Orico 20 Gbps M.2 NVMe Enclosure
If your PC is equipped with a USB 3.2 Gen 2×2 port or better, you may still want to max out the interface. Sequential transfer rates of more than 2,000 MB/s are better than 1,000 MB/s, after all, and will speed up your workstream if it includes moving large files such as video projects.
One option is the Orico 20 Gbps M.2 enclosure, which actually costs slightly less than the RGB-equipped Asus Strix Arion. This well-rounded aluminum enclosure is a bit heavier and larger than its 10 Gbps counterparts, but still fairly compact. You only have to bother with a single screw and it includes a heatsink as well as a 20 Gbps-rated Type-C to Type-C cable.
In short, it’s a solid product and a good representative for the 20 Gbps category. However, the advantages in practical terms remain somewhat limited.
Shopping links: Newegg
Fastest NVMe SSD Enclosures: 40 Gbps USB4/Thunderbolt
The fastest external NVMe SSD enclosures on the consumer market currently achieve 40 Gbps of bandwidth over USB4 or Thunderbolt. For now, these high-speed enclosures mainly cater to Mac and high-end PC users since these are the only platforms where 40 Gbps USB ports are widely available. However, an increasing share of new high-end PCs feature USB4 connectivity.
As for enclosures that match these specifications, there are several Thunderbolt-based variants on the market such as the Acasis TBU401. This one uses an Intel JHL7440 Thunderbolt 3 controller and offers sequential performance of around 2,700 MB/s when equipped with a sufficiently fast NVMe SSD. Like most of it’s competitors, it’s also larger than most USB 3.2 Gen 2 enclosures due to additional components and cooling requirements.
Shopping links: Amazon
Compatibility: Interface, M.2 Keying & Sizes
USB interface speeds are one thing, but you also want to ensure that your spare SSD is actually compatible with the enclosure. M.2 is not an interface but a form factor that may use the SATA or PCI-Express interfaces. Additionally, M.2 SSDs come in different sizes (lengths) and with different arrangements of pins (keying).
In most cases, this is easier than it looks. Most M.2 SSDs from recent years are of the M-key variety and are 80 mm in length (22*80*). Most enclosures will also accommodate any length except the extremely rare 22110 (110 mm) size. Again, most are 2280 except for special cases like the Steam Deck.
Many enclosures, including the above-mentioned Ugreen and SSK models, also support M.2 SATA SSDs using the B+M-key pin layout, but most will be PCIe/NVMe and M-key.
Almost any PCIe 3.0 (Gen3) or newer M.2 SSD should be able to saturate 10 Gbps or even 20 Gbps worth of USB bandwidth. For this reason, it makes a lot of sense to use an entry-level or midrange SSD for an external enclosure. Using a high-end drive means that much of its performance is left on the table.
This changes once you move up to 40 Gbps over USB4 or Thunderbolt. When buying this type of high-end enclosure, it’s worth checking the fine print (i.e. compatibility charts) and selecting the right SSD to make sure that it meets your expectations.
Wrapping Up
Looking a few years into the future, it’s a safe bet that USB4 will be more widespread than it is today. And USB-C ports are already replacing Type-A ports at a rapid pace, although the traditional port and interface is likely to live on for some time for compatibility reasons.
Since all 10 Gbps 3.2 Gen 2 SSD enclosures largely offer the same performance, the question that remains is whether it’s worth investing in a faster USB-C-based enclosure. For many users, this is a choice between retaining simple compatibility with older system on the one hand, and “future proofing” on the other. If you have no intention of using the enclosure with legacy hardware, a USB4 or Thunderbolt enclosure would make sense.
In all other cases, I would stick with the more widely compatible ones, as the performance advantages in real-world scenarios remain quite limited.
FAQ
How do I determine my USB port versions?
The easiest way to tell on a PC is by looking for the USB SuperSpeed logo next to the port. There should be a number next to it that denotes the bandwidth, e.g. 5, 10, or 20, which corresponds to the bandwidth in Gbps.
What are the different types of M.2 enclosures?
M.2 is not an interface but a form factor, and M.2 enclosures may support SSDs built for the SATA or PCI-Express interfaces. The SSD will in turn connect to the computer via a USB bridge or Thunderbolt controller chip in the enclosure. This is what determines what SSDs are compatible as well as the enclosure's maximum theoretical performance.
Some USB bridge chips like the Realtek RTL9210B support M.2 drives using either the SATA or PCI-Express interface, whereas others only support PCI-Express SSDs (utilizing the NVMe protocol). PCIe/NVMe M.2 SSDs are typically much faster than their less common SATA counterparts.
Is a DIY enclosure/SSD combo better than an external SSD?
Not necessarily, but it gives you more flexibility with capacity and performance configurations. External SSDs often use the same USB bridge chips/Thunderbolt controllers as those found in M.2 enclosures.
What is the best SSD to use in an enclosure?
Unless it's a high-end Thunderbolt or USB4 enclosure, the best SSD pairing is with an affordable mainstream drive. This is because just about any recent PCIe Gen3 or Gen4 M.2 SSD can saturate the bandwidth of a 10 Gbps or even a 20 Gbps USB port.
