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OWC Express 1M2 SSD review: USB4 storage finally arrives–and it's fantastic

OWC Express 1M2 USB4 SSDImage: Jon L. Jacobi

At a glance

Expert’s Rating


Over 3GBps transfers with USB4Works with all USB and Thunderbolt 3/4 portsAvailable unpopulated so you can leverage any NVMe SSD


A bit pricey when loaded with an SSDLarge (but beefy) for an external SSD

Our Verdict

You absolutely can’t beat the versatility (any USB or Thunderbolt port), or the performance (over 3GBps) of OWC’s Express 1M2 external USB4 SSD. It’s a tad large, but super sturdy, and especially affordable in its unpopulated flavor.

Price When Reviewed

1TB: $219.99 I 2TB: $299.99 I 4TB: $529.99 I 8TB: $1,299.99

Best Prices Today: OWC Express 1M2 USB4 SSD

RetailerPriceOWC$219.99View DealPrice comparison from over 24,000 stores worldwideProductPricePrice comparison from Backmarket

OWC’s Express 1M2 is the first USB4 SSD to show up on our doorstep. Or our building’s gated stoop, if I’m being 100 percent accurate. It’s a rather large external SSD that shows off USB4’s advantages nicely — i.e. Thunderbolt 4-like performance at a lower price point.

But before I get down to brass tacks, a short primer on what might be a new-to-you technology.

Further reading: See our roundup of the best external drives to learn about competing products.

What is USB4?

USB4 is a slightly less capable, but cheaper-to-implement subset of Thunderbolt 4, though it’s backwards compatible with older versions of USB — in other words, it has the same 40Gbps maximum transfer rate as Thunderbolt 4, so it can be just as fast, but there are less stringent requirements.

A USB4 drive can operate at 20Gbps if the vendor chooses, while a Thunderbolt 4 drive must operate at at least 32Gbps. USB4 lacks Thunderbolt 4’s dual-monitor capability, but supports DisplayPort 2.0 and 8K displays.

Finally, USB4 has a lower minimum voltage requirement of 7.5 watts as opposed to Thunderbolt 4’s 15W. Note that USB4 is Type-C connector only, so you’ll need an adapter for Type-A ports.

What are the OWC Express 1M2’s design and features?

The 1M2 looks like nothing so much as a large silver heatsink. (The pink hue in the pictures is due to lighting.) In fact, that’s what its case mostly is, though we’ve tested the OWC Aura Ultra IV TLC-based NVMe SSD that’s inside in a much smaller enclosure without eliciting extreme heat.

When I say large, I mean that the 1M2 measures 5.25-inches long, by 2.75-inches wide, by 0.75 inches thick and weighs a rather hefty 9.3 ounces. I personally quite enjoy the appearance and the heft — it looks like it means business. Tastes vary.

While the Express 1M2 won’t fit in a shirt pocket, it will fit in a jacket side pocket and isn’t overly burdensome in a backpack. The fins are rounded on the corners, but a bit rough on the sides. In other words, it might be slightly prone to snagging on loose material. That shouldn’t dissuade you from purchase, but being picayune is why I’m paid the big bucks.

As intimated in the primer above, the 1M2 may be connected to any USB port, though performance will vary according to the standard: approximately 3GBps with USB4/Thunderbolt 4 ports, 2GBps with 20Gbps USB(3.2×2), just over 1GBps with 10Gbps USB (3.x), and around 500MBps over older 5Gbps USB 3.

Note that when attached to a Thunderbolt 3 port, the drive runs at 20Gbps — a limitation of Thunderbolt 3, not the drive.

How much is the OWC Express 1M2?

The OWC Express 1M2 is available unpopulated (no drive inside) for $120, as a 1TB drive for $220, 2TB for $300, 4TB for $530, and 8TB for $$1,300. For such a fantastic enclosure, $120’s not a bad price; however, you’re paying a premium for having OWC populate it for you.

Jon L. Jacobi / Foundry

The OWC Express 1M2 is currently the best thing going in an external SSD, assuming you’re not looking for something that will fit in your shirt pocket.

How fast is the OWC Express 1M2?

Before settling in to benchmark the 1M2 I attached it to variety of connections from USB 2.0 to Thunderbolt 4. (Our test bed lacks a USB4-only port.) The drive functioned perfectly on all of them, albeit limited to the maximum speed of the bus in use.

Note that I had to enable Better Performance/Enable Write caching under the drive’s (not the partition’s) policies to achieve full performance. This was possibly due to our test bed not fully recognizing the new flavor of USB.

As you can see below, the Express 1M2 easily outstripped our former champion, OWC’s own Envoy Pro FX in the CrystalDiskMark 8 sequential tests. We also tested the Express 1M2 on 20Gbps and 10Gbps USB ports.

Nothing changed in the CrystalDiskMark 8 4K tests — the Express 1M2 remained far ahead of the competition.

In our real-world 48GB transfers, the Express 1M2 reigned supreme. Notice that the 1M2’s 20Gbps aggregate time was better than the 20Gbps Crucial X10 Pro’s. Indeed, OWC takes the overall USB 20Gbps performance title from that worthy competitor.

Finally, a hint of humility was required from the Express 1M2, as the 1TB version that OWC sent us ran out of secondary cache before the 450GB write was completed and finished second to the 2TB Crucial X10 Pro.

Even off cache, write speed was between 500MBps and 650MBps — hardly tragic like the 100MBps that you’ll see with QLC drives.

What’s not illustrated by these charts is that the Express 1M2 was the fastest external drive we’ve tested over every bus: Thunderbolt 4, 20Gbps USB, and 10Gbps USB. No matter which you’re rocking, the 1M2 is the drive for speed.

The Express 1M2 also formatted, trimmed, etc. quite rapidly, though that’s likely due to the Aura Ultra IV SSD rather than the enclosure. Also, despite the massive heatsink, the Express 1M2 still ran mildly warm to the touch over the Thunderbolt 4/USB4 and USB 20Gbps ports, so we can see the need for said heat spreader.

Should you buy the OWC Express 1M2?

The OWC Express 1M2 is currently the best thing going in an external SSD, assuming you’re not looking for something that will fit in your shirt pocket. It’s the fastest we’ve tested over any flavor of USB or Thunderbolt, and is built like a brick outhouse.

Crème de la crème or not, buying the unpopulated version and installing a bargain SSD is by far your best deal. Even the slowest PCIe 3.0/4.0 NVMe TLC SSD we’ve tested should deliver roughly the same performance as even at 40Gbps, the bus is the limiting factor.

How we test

Drive tests currently utilize Windows 11, 64-bit running on an X790 (PCIe 4.0/5.0) motherboard/i5-12400 CPU combo with two Kingston Fury 32GB DDR5 4800MHz modules (64GB of memory total). Both 20Gbps USB/Thunderbolt 4 are integrated to the back panel and Intel CPU/GPU graphics are used. The 48GB transfer tests utilize an ImDisk RAM disk taking up 58GB of the 64GB of total memory. The 450GB file is transferred from a 2TB Samsung 990 Pro which also runs the OS.

Each test is performed on a newly formatted and TRIM’d drive so the results are optimal. Note that in normal use, as a drive fills up, performance may decrease due to less NAND for secondary caching, as well as other factors. This is less of a factor with the current crop of SSDs with their far faster NAND.

Caveat: The performance numbers shown apply only to the drive we were shipped and to the capacity tested. SSD performance can and will vary by capacity due to more or fewer chips to shotgun reads/writes across and the amount of NAND available for secondary caching. Vendors also occasionally swap components. If you ever notice a large discrepancy between the performance you experience and that which we report, by all means, let us know.

Best Prices Today: OWC Express 1M2 USB4 SSD

RetailerPriceOWC$219.99View DealPrice comparison from over 24,000 stores worldwideProductPricePrice comparison from Backmarket

Jon Jacobi is a musician, former x86/6800 programmer, and long-time computer enthusiast. He writes reviews on TVs, SSDs, dash cams, remote access software, Bluetooth speakers, and sundry other consumer-tech hardware and software.

Recent stories by Jon L. Jacobi:

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