Seagate's LaCie Rugged SSD4 (starts at $179.99 for 1TB; $619.99 for 4TB as tested) external SSD looks a lot like many of the company's rugged storage products. Deep in the specs, though, it boasts a big difference: USB4 connectivity and the blazing speeds that interface offers. It also supports Thunderbolt 4 and 5 and is speedy over both interfaces, though its Thunderbolt 5 speeds fell well short of what we saw from the LaCie Rugged SSD Pro5. The ruggedization features are welcome, though they don't provide full protection against dust and water. We're still partial to LaCie's own Editors' Choice-award-winning Rugged SSD Pro for all-around protection, if not absolute peak speeds.

Design: Orange Is the New...Orange

Anyone familiar with LaCie's rugged storage products will recognize the SSD4's look: the metal drive unit is clad in a rubbery pumpkin-orange bumper that looks a lot like a life raft. The bright color makes the drive stand out in low light, like the safety vests worn by highway workers, bicyclists, and others at night. Meanwhile, the brushed-aluminum case shows through on the top and bottom, and you can remove the drive unit from the sleeve if need be.

(Credit: Joseph Maldonado)

In the middle of one of the short ends of the SSD4, you'll find a USB Type-C port that supports USB4 or Thunderbolt 5 connectivity, as well as earlier, slower variants.

(Credit: Joseph Maldonado)

The drive comes with a small orange port cap to protect the USB-C connection when it's not in use—but the cap isn't tethered to the bumper, so you'll need to be careful not to lose it. (It's visible alongside the drive in the image on the box above.) One option: You can tie the cover to the rest of the case, though we're not sure why Seagate didn't include an optional tether cord or something more elegant than a homegrown solution.

(Credit: Joseph Maldonado)

As an aside, when you remove the port cover, you'll see "design by neil poulton," LaCie's nod to the award-winning designer of its rugged storage products. (And, yes, the lowercase is correct.)

Features: How Tough Is Tough Enough?

Just how effective is that cover? The LaCie SSD4 has an ingress protection (IP) rating of IP54, meaning that when the end cap properly seals the port, the drive is dust- and water-resistant. Note that it's not totally protected from the elements, though. The first number in the IP rating (5) indicates that dust can still get in, but not enough to interfere with the SSD's operation. The second number (4) indicates that the SSD4 is splash-resistant.

That's good coverage for casual hazards, but it's modest compared with the LaCie Rugged SSD Pro5 and its IP68 rating—meaning it's impervious to dust and extremely resistant to water, allowing immersion up to 3 meters. LaCie rates the drive's drop tolerance at 3 meters and says the unit can survive being run over by a car weighing up to 1,300 kilograms (1.3 tons). A Fiat subcompact, fine; a Ford F-150, not so much.

For a different kind of protection, LaCie includes a three-year warranty and a three-year Data Recovery Service subscription.

As noted earlier, we tested the 4TB version of the unit, and the lowest-capacity model is a 1TB. Below is a breakdown of the available models (including LaCie's middle 2TB version) and their list prices.

Note that when we wrote this, LaCie was touting all these drives on its online store at 25% off list price, but they were all out of stock there, and only spottily available at the usual retailers. We'll have to see if the drives revert to MSRP when they come back in stock.

Performance Testing: Better Over USB4 Than Thunderbolt 5

We put the LaCie SSD4 through our usual suite of benchmark tests for external solid-state drives: Crystal DiskMark 6.0, PCMark 10 Storage Overall, 3DMark Storage, Blackmagic's Disk Speed Test, and our own folder transfer test. The first three are run on a PC with the drive formatted in NTFS, and the last two on a MacBook Pro using the SSD4's native exFAT format.

In addition to the Thunderbolt 4-equipped MacBook Pro that we typically use for testing external SSDs, I enlisted a 14-inch MacBook Pro (model A3403) with an Apple M4 Pro CPU for testing the SSD4 over a Thunderbolt 5 connection. After running the Thunderbolt 5 Mac tests in exFAT, I reran them after formatting the drive in APFS (Apple File System), the current native file system for Apple devices. The results were nearly identical to the exFAT results, which are included in the table below.

First, let's look at the Windows-based testing, performed on our new USB4 testbed. In Crystal DiskMark, the SSD4 turned in impressive numbers, with sequential read and write speeds virtually identical to those of the USB4-supporting Corsair EX400U. Both machines cleared their rated sequential read speeds, with the fastest results we have seen on an SSD in Windows testing. Still, both fell well short of their write-speed ratings.

In the PCMark 10 Storage data-drive test, the SSD4 turned in the highest score in our comparison group, edging out the LaCie Rugged SSD Pro5, as well as the Corsair. The USB 3.2 Gen 2x2 drives fell well below the trio.

The 3DMark Storage gaming-centric benchmark showed near parity between the USB4 and USB 3.2 Gen 2x2 SSDs, with only an 11% difference between the lowest and highest scores in our comparison group. The SSD4's results fell smack in the middle of this narrow range.

(Credit: Joseph Maldonado)

Then came the Mac-based Blackmagic Disk Speed Test. When tested over a Thunderbolt 4 connection, the SSD4's read and write speed results were nearly identical to those of the Corsair EX400U. The SSD4 turned in considerably better scores with Thunderbolt 5—but they still fell well below LaCie's Rugged SSD Pro5 tested on Thunderbolt 5. Between those two LaCie drives, the SSD4 wins on USB4, while the Pro5 is better on Thunderbolt 5.