Thunderbolt 5 📉 The connection of the future that doesn't work well yet 😤

Thunderbolt 5. The cutting edge of connections. All of it: monitors, a Thunderbolt 5 dock, and even a Thunderbolt 5 SSD were on my desk. I was happy, as only tech geeks can be, to have a device that few others possess. 😄

A few days later, I was more than happy to tear it down and return to a slower, more functional Thunderbolt environment. I'm just not sure the Thunderbolt 5 ecosystem is ready for the masses.

This isn't about criticizing Thunderbolt 5 itself. Rather, it's about the headaches that can accompany not one, but a multitude of devices, all interacting with each other in unexpected ways. Add in software, drivers, firmware updates, and the like, and it's hard to point the finger at any particular component. This is what testing next-gen hardware can mean: dealing with technology that should work well, but doesn't. 🤔

Thunderbolt 5: The next generation of connections

Thunderbolt 5 was announced about a year ago as the next step in the evolution of the Thunderbolt connection standard. Thunderbolt wasn't necessarily designed for power users, but the best Thunderbolt 3 and Thunderbolt 4 docks allow users to connect a pair of 4K displays to their desktop running at 60Hz. I find this extremely useful for my productivity, as I can organize multiple windows of email, chats, calendars, web browsers, and more across two or more screens. 💻

Both Thunderbolt 3 and 4 offer 40Gbps throughput. Thunderbolt 5 takes this to 80Gbps, and in certain situations up to 120Gbps. This additional bandwidth fits perfectly into the workspace. gaming and productivity, supporting up to three 4K displays at 144Hz, two 8K displays at 60Hz, or a single 1080p display at 540Hz. (Intel hasn't yet finalized the details of these last two resolutions.) Additionally, Intel notes that Thunderbolt 5 should be able to power external GPUs, a capability that was omitted in Thunderbolt 4. 🎮

The problem is that Thunderbolt 5 hardware is scarce, period. While some of the first Thunderbolt 5 docks were shown off last January, it's now October, and pretty much the only dock I've seen advertised is Kensington's SD5000T5 EQ, which I recently got my hands on. There are also few Thunderbolt 5 cables on the market.

But a first experience isn't a proof, and I was eager to get my hands on the hardware that would allow me to put the Kensington SD5000T5 through its paces: connecting it to three 4K144 displays via a laptop with Thunderbolt 5 connections and, as a bonus, seeing if I could find an SSD that would run at Thunderbolt 5 speeds. ⚡️

I didn't expect it to be easy. For some reason, devices with Intel's Thunderbolt 5 host and accessory components ("Barlow Ridge," or the Intel JHL9580 and JHL9480) have been few and far between. Docks remain scarce, as I mentioned, and as far as I know, only two notebooks come with a Thunderbolt 5 controller (not integrated): a version of the Razer Blade and the Maingear ML-17.

Luck was on my side. The Kensington SD5000T5 was sitting on my desk, and Maingear agreed to send me an ML-17 for review. A colleague was also in the process of reviewing a pre-production version of OWC's Envoy Ultra Thunderbolt 5 SSD and agreed to let me try it out for a while in exchange for some benchmark results. Everything seemed to be going well. 😅

Thunderbolt 5 started badly, then got worse

A few days later, I had finished all my current projects and sat down to play with the next generation of connectivity power. I updated the ML-17 with necessary Windows updates, Microsoft Store updates, available firmware updates, and more. Maingear sent me the notebook with the updated Intel Driver and Support Assistant, so I was pretty confident I had the latest hardware and drivers.

The first steps were quite positive. As most gamers know, gaming laptops include a heavy power brick that ends in either a cylindrical connector or a square power connector. One of the benefits of Thunderbolt 5, however, is its ability to theoretically supply up to 240W of charging. Being able to connect the gaming laptop to the Thunderbolt 5 dock and power it on without needing the laptop's cumbersome external power connector made me quite happy.

Well, sort of. I later discovered that the dock could only power the laptop through one of its two Thunderbolt 5 ports, and when I measured it with a USB power meter, I found it couldn't deliver more than 87W, even while gaming. 😕

Maingear's Thunderbolt 5 ports are not specifically labeled as Thunderbolt 5 ports, just a generic Thunderbolt connection.

The 240W power delivery requires explicit support from the laptop, dock, and cable, and I wasn't surprised that it didn't live up to my expectations. Unfortunately, the trend continued.

Acer kindly supplied three of its Nitro XV5 displays (XV275K) for testing. All three displays run at up to 144Hz via the HDMI port and up to 160Hz via the USB-C/DisplayPort, which should have been enough to deliver on Thunderbolt 5's promise of rendering a 144Hz image across three 4K displays.

Unfortunately, that didn't happen. The Maingear laptop output an image on only two of the displays plus the laptop itself. (Thunderbolt 4 docks can output to two 4K displays in addition to the laptop, so I have no reason to believe my interpretation of "three displays" was wrong.) While one laptop could render at 4K 144Hz without issue, it was a challenge to get the other to do so at 1440p—it took me unplugging and replugging to get it right once, slowly. I couldn't repeat this consistently.

(The Kensington dock provides three upstream Thunderbolt 5 ports. I used the Kensington USB-C to HDMI adapter to connect one display, plus two uni 4K60 USB-C to DisplayPort cables — which are rated only for 1440p165, not 4K — for the others. I expected all three displays to power on. They didn’t.)

In fact, the entire setup felt very sluggish when browsing the laptop and through a web browser—something you wouldn't expect with a high-end Intel CPU and Nvidia GeForce RTX 4090 GPU inside. I'm pretty sure the Thunderbolt connection had a negative impact. Streaming a 4K video at 60Hz stuttered severely when running on the external display connected to the Thunderbolt dock—more than 30 percent of frames were dropped. Playing the same video on the laptop by itself wasn't perfect, but it was much, much better.

Maingear blamed this on the Thunderbolt 5 cable. “I haven’t tested a multitude of cables yet, but the Apple TB5 Pro cable has consistently worked for us,” a Maingear representative wrote in an email. “Where I could use a decent USB-C cable on Thunderbolt 4, Thunderbolt 5 seems to work best with certified Thunderbolt 5 cables.”

That may be true, but the Kensington Thunderbolt 5 cable was labeled correctly and should be certified. And why would I need to buy an Apple cable to get my PC docking station working? 😩

OWC Envoy Pro FX SSD. This isn't the Envoy Ultra Thunderbolt I borrowed. Unfortunately, I forgot to take a photo before sending it back, but the design is basically the same.

Storage performance also suffered

When I connected the SSD, the performance of my Thunderbolt 5 test setup was equally poor. I normally run PCMark's External Storage test to test a dock. My colleague Jon Jacobi prefers to run specific storage tests to assess SSD performance directly. I prefer PCMark, whose External Storage test reports the SSD's "bandwidth." That's what I'm looking for: how much data does the drive have to handle?

I also run a second test, recording the time it takes to copy a folder full of media and other files from the SSD, through the dock, to the laptop. I do all of this. that on its own and also while streaming a 4K video at 60Hz over the internet via the Thunderbolt cable, just to see if a background file transfer will affect performance.

The experience, frankly, was horrible. While running the PCMark test with the SSD connected directly, I got a score of 1,743 or 252.3 MB/s. But when connected to the dock, the SSD's PCMark score plummeted to just 1,108 or 159.3 MB/s. Was it the dock's fault or the Thunderbolt 5 connection? One of the two, probably.

When I connected the SSD directly to the laptop and copied my folder to the desktop, it took an average of one minute and five seconds. While streaming video, the same task took 58 seconds longer, or two minutes and three seconds. That seemed pretty extreme.

Interestingly, when I connected the SSD to the dock and then ran the folder copy, it finished in 41 seconds—much faster! But performing the folder copy while streaming video took two minutes and six seconds, again with the SSD connected to the dock. (The internet connection was provided via Ethernet, which remained connected. But letting the system use Wi-Fi didn't seem to make any difference.)

It's worth noting that when I tested the Kensington dock on a "normal" Thunderbolt 4-equipped laptop with a slower SSD, the dock worked "normally" as well. 📈

In recent years, we've seen some strange performance benchmarks, such as benchmarks of mobile CPUs running on battery power outperforming the same laptop while plugged in. Still, the varied results, including the annoying stuttering when playing video, tell me something's not quite right. What is it? I don't know, which is putting me off the whole Thunderbolt 5 experience.

Should you buy Thunderbolt 5? Not right now.

By testing a single device, a good review works to isolate the variable. Desktop CPUs are tested with the fastest possible GPUs, with common motherboards, memory, and storage (if possible), so that any differences in performance can be directly attributed to the new CPU.

Maingear's Windows 11 Settings menu lists the controller as USB4 v2, which should be essentially identical to Thunderbolt. I don't find any specific mention of "Thunderbolt" in Settings or Device Manager, just USB4.

In this case, I'm testing a new dock, laptop, and SSD, with new cables connecting them. That's at least three unknowns I can't really unpack. So Maingear may accuse the cable of being defective, while I suspect the Maingear hardware may be at fault. I can't know for sure.

What makes me doubt is the relative shortage Thunderbolt 5 hardware, even as early as late 2024. Intel has launched its Lunar Lake and Arrow Lake chips, and neither includes an integrated Thunderbolt 5 controller. Intel gave some good reasons for excluding it — desktop makers prefer to “upsell” using discrete components, for example — but the instability I’m seeing makes me wonder if there’s something else going on. 🤨

I'm not ruling out Thunderbolt 5 at all. An updated driver could potentially fix this issue, or it might require a more sophisticated hardware revision of Intel's own Barlow Ridge controller. I don't know.

For now, however, I would not recommend invest in the ecosystem Thunderbolt 5.

In summary, Thunderbolt 5 It undoubtedly represents a significant advance in specifications and performance 🚀, promising greater bandwidth and new capabilities that could revolutionize the experience for demanding users and gamers 🎮. But the current reality falls far short of that promise.

A shortage of compatible hardware, stability issues ⚠️, power delivery limitations ⚡, and overall performance inconsistencies show that the Thunderbolt 5 ecosystem is not yet mature or ready for mainstream use.

For those who value reliability and proven functionality, it's wisest to wait for manufacturers to work out these details and for the market to offer more robust and reliable solutions 🛠️.

In short, Thunderbolt 5 is a technology with a future 🌟, but its present invites caution and patience ⏳.