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OWC Express 4M2 4-Bay USB4 External SSD Enclosure

BH #OWCUS4EXP4M2 • MFR #OWCUS4EXP4M2
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OWC Express 4M2 4-Bay USB4 External SSD Enclosure
Key Features
  • 4 x NVMe M.2 SSD Slots
  • Supports M.2 2230, 2242, and 2280 SSDs
  • 40 Gb/s USB4 Interface
  • Up to 3200 MB/s Data Transfer Speed
Built to handle high speed backups, multiple media card offloads, and intense raw photo and 8K video editing sessions, the Express 4M2 4-Bay USB4 External SSD Enclosure from OWC / Other World Computing is designed for DITs and filmmakers, professional video editors, VFX artists, colorists, photographers, and other creative. Equipped with four NVMe M.2 SSD slots, the Express 4M2 supports four M.2 2230, 2242, or 2280 SSDs. Depending on your choice of SSD, data transfers speeds can reach as high as 3200 MB/s. OWC built the Express 4M2 with a software RAID controller that supports RAID 0, 1, 4, 5, 6, and 10, each of which provides performance, data redundancy, or a combination of both. For those who do not need a RAID, JBOD is also available.
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OWC 4M2 Overview

Built to handle high speed backups, multiple media card offloads, and intense raw photo and 8K video editing sessions, the Express 4M2 4-Bay USB4 External SSD Enclosure from OWC / Other World Computing is designed for DITs and filmmakers, professional video editors, VFX artists, colorists, photographers, and other creative. Equipped with four NVMe M.2 SSD slots, the Express 4M2 supports four M.2 2230, 2242, or 2280 SSDs. Depending on your choice of SSD, data transfers speeds can reach as high as 3200 MB/s. OWC built the Express 4M2 with a software RAID controller that supports RAID 0, 1, 4, 5, 6, and 10, each of which provides performance, data redundancy, or a combination of both. For those who do not need a RAID, JBOD is also available.

The Express 4M2 may be formatted for use with macOS 14 and later, Windows 10 (32-/64-bit), Windows 11, and Windows Server 2016, 2019, or 2022. It connects to your host system using a 40 Gb/s USB4 port, but is backward compatible with 10 Gb/s USB 3.2 Gen 2, which delivers real world speeds of up to 990 MB/s. Its aluminum enclosure offers rugged protection while keeping the drive cool for improved performance, although additional cooling is provided by dual 40mm fans that spin up to 4000 rpm. The Express 4M2 may also be used as a boot drive, but only on Mac. It is plug-and-play, meaning no drivers are required for use, while bus power means that the drive is powered solely using the included USB-C cable.

The DIY RAID You Wanted
OWC heard you loud and clear (pun intended) when you said you loved everything about the Express 4M2 but wanted it quieter. After adding smart adaptive fans that only turn on when needed for near silent operation, we decided to give it USB4 connectivity for the optimum blend of compatibility, performance, and affordability. Now you can build a desktop/shuttle high-performance RAID with your choice of NVMe M.2 SSDs and get up to performance up to 3200 MB/s with USB4, Thunderbolt, and USB-C Macs and Windows computers.
Maximum Speed from Your Machine
The Express 4M2 is the fastest multiple NVMe SSD enclosure OWC offers and was purposefully built so you can utilize the maximum performance capability of your Mac or Windows computer with full compatibility. When connected to a 40 Gb/s USB4 port on Macs with Apple Silicon (M1/M2/M3/M4), 40 Gb/s USB4 ports on Windows, and Thunderbolt 4 or 5 on Windows or Mac, you'll get speeds up to 3200 MB/s. 40 Gb/s Thunderbolt 3 on Intel Mac yields speeds up to 3000 MB/s, while Thunderbolt 3 or USB 3.2 Gen 2 on Windows runs as 10 Gb/s USB 3.2 Gen 2 at speeds up to 990 MB/s.
The Power of Choice is Yours
Engineered to support most NVMe M.2 2230, 2242, or 2280 SSDs, this compact powerhouse gives you the ultimate flexibility to choose the drive you want today - including OWC Aura SSDs with a massive capacity of up to 8TB each. When tomorrow's 16TB and larger drives hit the scene, you can easily boost your Express 4M2's capacity.
One Cool RAID for Diverse Workflows
High speed backups, multiple media card offloads, and intense raw photo and 8K video editing sessions mean one thing... heat. You can put aside any thermal throttling and noise concerns because the Express 4M2 utilizes a heat dissipating solid aluminum body along with smart, adaptive fans that activate only when needed or under heavy loads. Diversity of use also means being able to easily work cross-platform with Macs and Windows computers. OWC help you keep your cool in mixed environments with their MacDrive software (available separately).
The Express 4M2 Is Ideal for:
  • DITs and filmmakers wanting to build an affordable yet high-performance NVMe SSD RAID with up to 32TB of capacity, RAID 5 capabilities, and the ability to deliver maximum offload speeds and thermal stability when backing up media cards from multiple cameras on set.
  • Professional video editors, VFX artists, colorists, and high-volume photographers seeking an easy DIY assemble high-performance NVMe SSD RAID to handle demanding post-production and editing workflows including 8K RAW video, VFX compositing work, multi-cam sequences in 4K raw or ProRes video, and batch editing ultra-high-resolution pictures.
  • Anyone looking for a lower cost RAID option to the four NVMe M.2 based OWC ThunderBlade and are willing to accept the Express 4M2's larger form factor, fan cooling, no additional connectivity ports, and no ballistic shipping case for shuttle use.
Powerful RAID Tool
SoftRAID (sold separately) is a fast and flexible application to configure, maintain, and protect your RAID volumes on Mac and Windows.
  • High performance RAID 0/1/4/5/1+0 (10) volumes
  • Predictive Health Monitoring proactively notifies of volume and disk issues well before failure, provided on your computer and remotely
  • Seamless Cross-Platform Sharing with support for Apple-formatted APFS and HFS+ SoftRAID volumes between Mac and Windows at no additional cost
  • 35+ years of experience with pro support to provide peace-of-mind with setup help, ongoing questions, or urgent disk issues
  • And many more unique features
Note: M1 Macs require macOS 11.3 or later. SoftRAID is licensed per computer.

 

OWC 40 Gb/s USB-C Cable Included
OWC Express 4M2 comes with a OWC 28" 40 Gb/s USB-C cable. But if your workflow demands a different length to make the connection, OWC USB4 Active Optical Cables are a great choice.
UPC: 810179170721

OWC 4M2 Specs

Key Specs
RAID
Yes: Supported RAID Modes: 0 / 1 / 4 / 5 / 10 / JBOD
Number of Bays
4x M.2 (2280) NVMe
Inputs/Outputs
1x USB-C (USB4) Input/Output
Computing
Bridge Chipset
ASMedia ASM-2464PDX
Drives
RAID
Yes: Supported RAID Modes: 0 / 1 / 4 / 5 / 10 / JBOD
Transfer Rates
3200 MB/s
General
Number of Bays
4x M.2 (2280) NVMe
Inputs/Outputs
1x USB-C (USB4) Input/Output
Media Card Slots
No
PCI Expansion
No
Software
OS Compatibility
Windows 10 or Later
Windows Server 2016 to 2022
macOS 14 to 15
Security
Security Features
No
Electrical
Input Power
100 to 240 VAC, 50 / 60 Hz at 1.5 A
PSU
1 x 18 W
Physical
Operating Conditions
32 to 104°F / 0 to 40°C
Storage Conditions
-4 to 158°F / -20 to 70°C
Certifications
CE, FCC, ICES, RCM, UKCA, VCCI
Cooling
2x 4000 rpm 40 mm Fans
Material of Construction
Aluminum
Cable Length
28" / 0.7 m
Dimensions
7 x 5.5 x 2.4" / 17.8 x 14 x 6.1 cm
Weight
4.0 lb / 1.8 kg
Packaging Info
Package Weight
4.85 lb
Box Dimensions (LxWxH)
11.3 x 8.4 x 3.5"

OWC 4M2 Reviews

Loud and More Limited Than Its Predecessor

By Paul
Rated 2 out of 5
Date: 2026-05-09

Both other reviews here are correct - it's louder than the original version, and not in a trivial way. It also lost functionality. The original had two TB ports AND a dedicated port for a monitor, effectively making it a little hub. Why did they remove these? No good reason except to squeeze out a little more profit. When memory has gotten so insanely expensive due to AI demand, it would be nice to have a full featured enclosure to make up for the price.

Excellent tool

By Stone
Rated 5 out of 5
Date: 2026-01-18

This has been an amazing tool for post production workflow. Fast speed and reliable, can be configured as needed- the price is incredibly reasonable, (despite the volatile market of SSD prices going bonkers) I set this up as a 32TB raid.

See any errors on this page?

Can this enclosure be used with WD Black 8TB ...

Can this enclosure be used with WD Black 8TB SN850X WITH the heatsink on the chips? Will they fit in the enclosure?
Asked by: Timothy
No, the OWC Express 4M2 4-Bay USB4 External SSD Enclosure does not fit the WD 8TB WD_BLACK SN850X Gaming Internal NVMe PCIe 4.0 SSD with Heatsink, BH # WEWDBB9H0080.
Answered by: JP A
Date published: 2025-08-13

If I select the SSD enclosure without softraid, ...

If I select the SSD enclosure without softraid, will I still be able to use RAID 0/1/5/10 via mechanical interface or JBOD only?
Asked by: Mark
You can use Apple's RAID assistant to do a software raid.
Answered by: David
Date published: 2025-12-01

Could this be used for a pc?

Could this be used for a pc?
Asked by: Nael
Yes, this OWC Express 4M2 4-Bay USB4 External SSD Enclosure is compatible with Windows PCs.
Answered by: Jordan K
Date published: 2025-10-23

is the Softraid license perpetual ?

is the Softraid license perpetual ?
Asked by: Bernhard
The OWC Express 4M2 4-Bay USB4 External SSD Enclosure with SoftRAID (B&H # OWUS4EXP4M2S) will come bundled with SoftRAID Premium for three years. After three years, you'll have the option to either maintain a free plan with limited features or upgrade to SoftRAID premium.
Answered by: Luis F
Date published: 2025-12-09
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