OWC Express 1M2 Review – Incredible USB4 SSD Speeds

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The OWC Express 1M2 is a bus-powered portable USB4 SSD, available in 1TB, 2TB, 4TB, or 8TB capacities or as an empty housing for installing your NVMe SSD. With the claimed speed of up to 3151MB/s, I was keen to test it out, hoping it would offer tangible improvements to my on-the-go photography workflow. The drive used in this review was retail-purchased.

OWC Express 1M2 Specifications

  • Length – 5.2″ (13.2 cm)
  • Width – 2.8″ (7.11 cm)
  • Height – 0.9″ (2.28 cm)
  • Weight – 253.0 g (0.56 lbs)
  • Drive Interface – M.2 supporting M.2 2230, M.2 2242, M.2 2280 “M Key” drives
  • Host Port – USB4 (USB-C) up to 40Gb/s (5000MB/s)
  • Real-World Speeds – up to 3151MB/s
  • Chipset – USB: ASM2464PD
  • Operating Temperature Range: 41°F to 95°F (5°C to 35°C)
  • Non-Operating Temperature Range: -4°F to 140°F (-20°C to 60°C)
  • Operating Humidity Range: 8% to 90% non-condensing
  • Non-Operating Humidity Range: 5% to 95% non-condensing
  • Capacities – 1TB, 2TB, 4TB, 8TB, empty.
  • Price$Check Current Price

In The Box

Express 1M2 and Thunderbolt 4 Cable

Being bus-powered, the contents of the OWC Express 1M2 box are simple. The drive comes with a 12″ 40Gb/s USB-C cable. Although OWC does not mention this in the specifications, the cable is marked with a Thunderbolt logo, making it Thunderbolt 4 compatible. Another logo indicates support for up to 240W Power Delivery.

Drive Configurations

User-replaceable SSDs in the Express 1M2 USB4 enclosure. Image courtesy of OWC.

The OWC Express 1M2 can be purchased with pre-installed OWC Aura NVMe SSDs in 1TB, 2TB, 4TB, or 8TB capacities. Alternatively, you can buy the empty drive enclosure and install your own SSD. The fact that the SSD is user-replaceable is huge for me. At the moment, I like the $/GB ratio of the 4TB drives, but in the future, when prices come down, I’m sure I’ll want to move to 8TB drives. Whenever that happens, I’ll be able to keep the same drive enclosures and simply order a new 8TB NVMe blade to go inside it. The process of swapping the internal drive is as simple as removing a few screws and sliding the drive out of its connector. Anyone can do it.

Express 1M2 Design and Features

The OWC Express 1M2 features a striking silver aluminum case covered in heat-sink blades. While this design makes the Express 1M2 less pocketable than other portable SSDs, the tradeoff is better performance and less throttling during prolonged read/write operations. Even with the heat sinks, this drive can get very hot while pushing it hard, so it’s easy to see that this design was necessary to extract the most speed out of today’s NVMe SSDs. This drive isn’t a subtle addition to your desk, but personally, I think it looks awesome.

The rear USB4 port on the Express 1M2 SSD.

The back of the Express 1M2 SSD enclosure features a single USB-C port labeled USB4 40Gb/s. The small circular indent above the USB-C port is threaded and compatible with OWC’s ClingOn cable clamp accessories. The base of the drive includes a pair of low-profile rubber feet, and the front of the enclosure has a white LED strip that glows when the drive is powered and flashes when the disk is being accessed.

The front of the Express 1M2 showing the disk access LED.

OWC Express 1M2 Speed Tests

OWC Express 1M2 tested on AJA System Test

Speed testing was performed using an M2 MacBook Air using AJA System Test and Blackmagic Disk Speed Test. Read speeds are slightly faster than the previous fastest SSD I have ever seen, the OWC Envoy Pro FX. On the other hand, write speeds are vastly quicker than anything I have ever seen. Write speeds are nearly double that of the Thunderbolt 3 OWC Envoy Pro FX! These results, over 3000MB/s for both read and write speeds, are astonishing.

OWC Express 1M2 tested on Blackmagic Disk Speed Test.

Photography Workflow Improvements

The recent introduction of USB4 CFexpress card readers has moved memory card download speed potential forward a considerable leap. Particularly when paired with CFexpress 4.0 cards that have read speeds exceeding 3000MB/s. Without an SSD capable of writing at a similar speed, many of these benefits would be lost when seeking a faster photo backup workflow. The OWC Express 1M2 solves this problem.

OWC Envoy Pro FX vs Express 1M2

I have previously reviewed the OWC Envoy Pro FX SSD, and until the new Express 1M2 came along, it was the fastest portable SSD I had ever used. The Envoy Pro FX features a Thunderbolt 3 port that also works over USB-3.2 for universal compatibility with Macs and PCs. Over Thunderbolt 3, my tests of this drive showed real-world write speeds of 1650 MB/s and read speeds up to around 2850 MB/s.

OWC Envoy Pro FX Thunderbolt 3 speeds.

The new Express 1M2 is sold for roughly the same price as the Envoy Pro FX (4TB prices are identical, 1TB and 2TB slightly different) but offers a larger maximum capacity of 8TB and the ability to upgrade your drives later. The USB4 connection on the Express 1M2 is compatible with both Macs and PCs and will show significantly improved maximum PC speeds on USB4 or Thunderbolt 4 equipped PCs (up to 3151MB/s) compared with the 990MB/s maximum of USB 3.2 from the Envoy Pro FX.

Given the overall higher performance, including dramatically increased write speeds, and upgradeability of the OWC Express 1M2 compared with the Envoy Pro FX, I honestly can’t think of a good reason to choose the Envoy Pro FX over the new, more future-proof Express 1M2. I have a couple of Envoy Pro FX drives and will replace them with the Express 1M2 immediately.


The OWC Express 1M2 is the fastest portable SSD I have ever tested. The 40GB/s USB4 connection delivers useful compatibility with Macs and PCs while extracting the most from current NVMe technology. The speed of this drive would be reason enough to buy it. The fact that you also upgrade the drives or buy the empty drive case and add your own drives is the icing on the cake.

While video editors will benefit most from the incredible 3000+MB/s read speeds of the Express 1M2, the workflow benefits of these kinds of read and write speeds shouldn’t be overlooked by photographers. Write speeds of 3000MB/s offer significant time savings for photographers downloading CFexpress cards onto the Express 1M2 using the latest CFexpress 4.0 technology, while the incredible read speeds drastically decrease preview render time in applications like Lightroom.

For the first time, using the Express 1M2 felt like I was working from the ultra-fast internal SSD of my M2 Macbook Air rather than an external USB drive. Workflow improvements were immediate, and the added cost of the Express 1M2 over a cheaper USB 3.2 10GB/s drive like the Crucial X9 felt worthwhile. I will continue to recommend the Crucial X9 for those on a tighter budget, or those needing a second-copy backup drive that can afford to be slower than the primary working drive (my current setup), but those looking for the absolute best portable SSD on the market should pick up an OWC Express 1M2. This drive easily earned the top spot in our guide to the best portable SSDs for photographers.

Where to Buy

As always, using our links for your purchases is appreciated. The OWC Express 1M2 is available from the links below. The current options include 1TB, 2TB, 4TB, 8TB, and an empty drive model that allows you to install your NVMe SSD.

Photo of author
Professional photographer based in Yukon, Canada, and founder of Shutter Muse. His editorial work has been featured in publications all over the world, and his commercial clients include brands such as Nike, Apple, Adobe and Red Bull.

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