If you're looking to take full advantage of the Thunderbolt 5 ports on your M4 Pro Mac mini or M4 Pro/Max MacBook Pro and possibly circumvent Apple's avaricious storage upgrade pricing, you should consider OWC's Envoy Ultra Thunderbolt 5 external SSD. The Envoy Ultra is hardly cheap, but it's nowhere near what Apple charges.
On the downside, there are more backwards compatibility issues than expected.
While the speed is alluring, and Thunderbolt 5 itself is backwards compatible with older Thunderbolt specs, it's not nearly as backwards compatible as you might think, we wish, or is hinted at.
First, you need a Thunderbolt 5-enabled Mac or Windows PC to take full advantage of Thunderbolt 5's 80Gbps transfer rates. 80Gbps? Yes. While you may have seen 120GBps quoted in some articles as Thunderbolt 5's top speed, that's only unidirectional for displays. Bi-directional, as with storage, is limited to 80Gbps.
The first compatibility issue is that to utilize a Thunderbolt 5 drive, Apple silicon Macs need either macOS 14 Sonoma, or macOS 15 Sequoia. Thunderbolt 3 Macs with Intel chips must run Sequoia. Note that the Envoy Ultra did enumerate on my Mac Studio Thunderbolt 4 bus when I was back on Ventura, but it wasn't available in Disk Utility or Finder.
Also, while the Envoy Ultra's captive cable prevents me from testing it on older Thunderbolt 1/2 using an adapter, the image above indicates that this is off the table. OWC confirmed that Thunderbolt 5 won't work with the older standards, so stick with Thunderbolt 3 equipment for older Macs.
Additionally, in my testing for PCWorld, there was a rather large issue with the official test bed. That issue is that the Envoy Ultra completely failed to register in the BIOS, Disk Manager, or Thunderbolt utility. Oops. This is despite updating all the drivers, removing everything non-essential, and even updating Windows 11 to the latest release on the test bed. Eventually, a BIOS/Thunderbolt firmware update from Asus solved the issue.
This iffy backwards compatibility could be a problem if you're working in a mixed operating system environment. Some older equipment might not be updated.
The OWC Envoy Ultra shares the handsome, sculpted styling of the Thunderbolt 3 40Gbps/USB 3.2 10Gbps Envoy Pro FX. However, it's a bit larger chunk of black metal, measuring about 0.75 inches thick, 2.8 inches wide, and 5 inches long. The Envoy Ultra weighs in at a satisfyingly substantial 10.5 ounces or so.
I already mentioned the captive cable, which is for weatherproofing (it's not IP-rated, but it seems as if it could pass the tests) and making sure you can't lose it. It does, however, make it a bit harder to stow the Envoy Ultra in tight quarters. Also, as with all captive cables, you should avoid stressing the attachment point for longevity's sake.
The OWC Envoy Ultra carries a three-year warranty, but no TBW (Terabytes that may be Written) rating was given.
If you thought a Thunderbolt 5 SSD was going to be cheap....well, I have some interesting real estate properties you might be interested in. The Envoy Ultra costs a cool $400 in its 2TB form and $600 at 4TB.
Given that you can grab a Thunderbolt 3/USB4 SSD for roughly half that, and a 20/10Gbps unit for far less than half, you'd better really need or want the speed. Note however, that despite a new 20Gbps 3.2×2 tunneling protocol that may work with docking stations, 3.2×2 SSDs still drop to 10Gbps when attached directly to a Thunderbolt 5 port. 20Gbps USB4 SSDs will operate at full speed attached to Thunderbolt 5.
Then again, compared with Apple's egregious price gouging for internal storage upgrades ($1,200 for 4TB???), the Envoy Ultra is a fantastic bargain.
Short answer: Very fast. Benchmarks showed anywhere from 5.2GBps (Blackmagicdesign's Disk Speed Test), to 6.5GBps reading (AmorphousDiskMark), to near 7GBps reading and 5.57GBps writing (ATTO). Even my real-world read of approximately 330GB of .mov files showed an excellent turn of form-almost 6GBps reading. Alas, writing was considerably slower, only around 1.5GBps.
Note I copied to and from the same M4 Pro MacBook Pro (2TB) that I ran the synthetic benchmarks on. By way of comparison, and for the enlightenment of those who might be looking to avoid paying ridiculous sums for Apple's internal storage, I included the benchmark results from the MacBook's internal SSD. These are shown to the right of the OWC Envoy Ultra's in the images below.
The difference between the internal and external storage isn't as severe as you might expect. Long story short, read results are remarkably close for the most part, though the internal SSD was a good deal faster writing under nearly all circumstances.
Note that the fastest external SSD we've previously tested, the USB4 Adata SE920 only just exceeded 3GBps reading. Yes...Very fast.
AmorphousDiskMark showed better numbers for the Envoy Ultra reading-a rather scintillating 6.44GBps. Not that far off the MacBook Pro M4 Pro's internal SSD. Approximately 5GBps writing from the Envoy Ultra seems to be the consensus from all three synthetic benchmarks.
ATTO Disk Benchmark paints largely the same picture, though read speeds for the Envoy Ultra actually exceeded those of the MacBook Pro M4 Pro's internal SSD. Writes? No, though around 5GBps is hardly anything to sneeze at.
Although our real-world file writes didn't match the benchmarks, they were still quite good. In total, the OWC Envoy Ultra is a very nice upgrade performance-wise from the average Thunderbolt 3 SSD, and a worthy companion for any Thunderbolt 5 Mac.
Note that the SSD inside the Envoy Ultra is the Auro Pro IV. You can read more about its performance (good at the time, not so much now) in sister publication PCWorld's review. That said, the Envoy Ultra, once running on our updated test bed, turned in a very, very slow 450GB write time.
If you want, and can afford the absolute fastest storage for your new Thunderbolt 5 Mac, then the answer is yes. Have at it. Also, it's a heck of a lot cheaper than Apple's rapaciously priced internal storage and nearly as fast. That said, Thunderbolt 3/USB4 SSDs are still plenty fast, cheaper, and far more compatible with older Mac hardware and software. I'll leave the value equation up to you.