Corsair delivers a USB4 SSD that I believe delivers on that technological promise

Corsair EX400U: 30-second review

There is a moment just before a Tsunami strikes when the sea starts to withdraw right before the wave arrives, and that’s where we are with USB4 storage.

While Thunderbolt SSDs have been around for a while for those with deep pockets, the promise of USB4 is ultra-high-speed external drives that are much more affordable.

Today, I’ve been sent the Crucial EX400U, a mainstream entrant that builds on this brand’s previous EX100U, a USB 3.2 Gen 2x2 drive, with something much more spectacular.

This small, 64mm square drive contains either 1TB, 2TB or 4TB capacity and promises read speeds of 4,000MB/s and write performance of 3,500MB/s. That, in theory, makes it as fast or faster as a typical Gen 3 internal NVMe drive, but this one connects using a USB4 port.

It will work with lower-specification USB-C ports, like those that use USB 3.2, but to get the full experience, it requires USB4 or Thunderbolt 4 ports.

Those systems with one of those ports, and fast enough internal storage to support these transfer speeds will get performance that is double that of the best USB 3.2 Gen 2x2 drives, and four times a standard USB 3.2 Gen 2 SSD.

There are some other less important selling points, and this drive doesn’t support hardware encryption, but for raw performance, it ticks all the boxes.

An obvious shoo-in for the best portable SSD, the EX400U is an affordable answer to the question, “Will that file transfer happen quickly enough to catch my ride home?”

Corsair EX400U: Pricing and availability

• How much does it cost? Starts from £140/$130
• When is it out? Available now
• Where can you get it? Sold through online retailers and also directly from Corsair.

When you offer, as Corsair does, a drive that can transfer files at twice the speed of a Gen 2x2 drive and four times the speed of a typical Gen 2 SSD, a price premium is to be expected.

The starting price direct from Corsair for the 1TB model in the UK is £139.99, with the 2TB and 4TB options being £199.99 and £359.99 respectively.

European pricing is €164.99, €239.99 and €424.99, and US customers pay $129.99, $189.99 and $349.99. However, at the time of writing, the 4TB models were out of stock across the board.

Comparing this to Corsair’s prior EX100U model, in the USA, the EX400U is roughly 45% more expensive for the same capacities but more than double the speed.

However, compared to the Nextorage NX-PS1PRO that I recently reviewed, which costs $249.99, $349.99, and $599.99 for the same capacities, the EX400U doesn’t look as deep a gouge.

With relatively few USB4 SSDs around, a differential is to be expected, but those wishing to have the extra performance will pay for that privilege, at least in the shorter term.

• Value: 4 / 5

Corsair EX400U: Specs

Corsair EX400U: Design

• Aluminium enclosure
• Only USB-C cable
• MagSafe

When placed alongside a popular USB SSD like the Crucial X9 Pro, the Corsair EX400U is thicker and square but not physically about the same length as its counterpart. There is some metal in this design, but parts of the case are also plastic, and it feels less robust than the Crucial X9/X10 line.

However, Corsair quotes the SSD inside as being able to withstand 1500g loading. That might seem plenty, but when fired, a typical artillery shell will experience somewhere from 15,000g to 30,000g. In short, it should handle being knocked off the table, but it has some limitations in that it’s not rated for water or dust encounters.

Along with the drive, Corsair includes a single 30cm USB-C to USB-C cable embossed with “40Gbps 240W,” which seems ideal for the job.

There is a killer feature that the EX400U was given that I’ve never seen on another USB SSD, in the form of a magnetic MagSafe-compliant ring on the underside.

As a technology journalist, I’d like to confront the myth that we all use Apple-branded equipment; I have zero, but even so, MagSafe is an incredibly useful option.

When you connect it to a laptop or even desktop, it’s possible to adhere it using the magnet to any ferrous metal surface, which prevents it from falling off and disconnecting.

The cost of adding this one feature must be minor, but it’s a stroke of genius that engineers included it on the EX400U.

Overall, this SSD might not be as robust as some competitor products, but it is sufficiently protected against office use unless someone decides it might make an excellent hockey puck.

It’s interesting to note that Corsair includes a three-year warranty with the EX400U, whereas the more robustly made Nextorage NX-PS1PRO is only covered for a single year.

• Design: 4 / 5

Corsair EX400U: Performance

• Needs USB 4.0
• Cache setting enhancements
• Excellent performance

It should go without saying, but there is little point in buying an EX400U if you don’t have a USB4 or Thunderbolt 4 port. It will work with USB 3.2, but performance will be capped at around 1,000MB/s on that interface.

To achieve the speeds I’ve documented, it also assumes that you have internal NVMe storage that is rated as quicker than 4000MB/s to send and receive data this rapidly.

These benchmarks reveal that the EX400U 2TB can match or better most of the speed tests I performed on the Nextorage NX-PS1PRO 2TB, which costs more.

To get these top speeds, write-caching needs to be enabled in the device manager, but Corsair is upfront about this in its notes.

One result that needs some explaining is the AJA System Test, where the caching method on the EX400U delivers lower results than the NX-PS1PRO.

Looking at the graphs, the NX-PS1PRO makes a slightly odd write pattern where data is written in chunks at around 2700MB/s, and then every 1500MB or so, it would briefly drop to 1200MB/s. Conversely, the EX400U would operate at full speed with closer slowdown spikes until it ran out of system RAM for the cache, roughly at the 48GB point, and then it would decline for the final quarter of the write operation.

For most of the write, the EX400U would hit 3200MB/s, but the drop off after 48GB reduced the average score to 2638MB/s. If the file was smaller than 48GB, the EX400U was faster in both writing and reading.

Like the Nextorage product, the Corsair EX400U doesn’t support hardware encryption, but you can use software encryption to protect sensitive documents stored on the drive.

Overall, the speed of this drive is what those with USB4 and Thunderbolt 4 ports have been waiting for.

• Performance: 4.5 / 5

Corsair EX400U: Final verdict

Unless you want a more flexible caddy solution or hardware encryption that you can get with the Ugreen USB4 Enclosure, the Corsair EX400U is the drive to be using on USB4.

Where the older EX100U didn’t provide the entire Gen 2x2 experience, this drive does great service to USB4 as a standard and shows how useful it might be in the future.

However, the EX400U isn’t perfect and leaves room for an enhanced EX500U.

At this price point, hardware encryption should have been included. I thought that all of Corsair’s MP600 series supported this technology, but I now suspect that the MP600 Micro models don’t, and my guess is that is what is inside the EX400U.

The only drives from the Corsair M.2 collection that would physically fit are a 2230 or 2242 drive, and the MP600 Core Mini drives do have encryption, leaving only the MP600 Micro as the likely candidate.

That might also explain why the 4TB model appears to be missing in action so far since Corsair has yet to release a 4TB option on that drive. Taking that extrapolation another step might be a long time before Corsair introduces an 8TB model, as fitting that onto a 2242-sized M.2 module could be a big challenge.

Those points aside, the Corsair EX400U is the most affordable USB4 drive so far. It throws the gauntlet down at the feet of Samsung, SanDisk and Crucial, and I’m genuinely excited to see the competing hardware from them and others.

Should I buy the Corsair EX400U?

Buy it if...

Don't buy it if...

Also consider

Nextorage NX-PS1PRO Series
One of the first USB 4.0 capable external SSDs available, the Nextorage NX-PS1PRO Series comes in 1TB, 2TB or 4TB capacities. Similar performance to the EX400U, but larger and more expensive.

Read our full review of it here.

OWC Envoy Pro FX
If you have Thunderbolt 3 ports or intend to add this functionality soon, then the Envoy Pro FX might well be worth your time. A beautifully engineered external storage option that can provide exceptional performance in the right circumstances, the OWC Envoy Pro FX is effective if expensive.

Read our full review of the OWC Envoy Pro FX

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