If your computer has a modern Thunderbolt port, you’re probably not getting as much out of it as you could. Thunderbolt is one of the fastest, most versatile connection standards in the world of computers, but most people just use them as glorified USB ports—which arguably they are, but I digress.
Thunderbolt ports might just look like USB-C, but they’re hiding a PCIe superpower that allows for external peripherals to connect directly with your computer’s core hardware as if it were a card installed on the motherboard. That opens up some audacious possibilities.
5
Run an External GPU Like It’s Native
If you have a laptop or mini PC with Thunderbolt, you (usually) have the option to connect an eGPU (external GPU) to it as if you’d slotted it into the motherboard itself. The catch here is that Thunderbolt, even the fastest Thunderbolt 5, is quite a bit slower than a modern PCIe slot on a motherboard. So you’ll run into the same issues you’d get with a card running at slow PCIe speeds—low bandwidth.
That said, this is only a problem when it’s a problem. If your laptop or mini PC is running on integrated graphics, hooking up a midrange eGPU using Thunderbolt will absolutely blow that out of the water, but if you try to connect a high-end GPU and play games at high resolutions like 4K UHD, then the performance will take a dip compared to what the card is really capable of.
There are alternatives, such as OCuLink, which can offer better bandwidth and less latency, but Thunderbolt is something your current computer is more likely to have, and you can’t just add OCuLink to a laptop or mini PC.
Sadly, Apple Silicon Macs are not compatible with eGPUs under macOS—even though the Thunderbolt interface itself could technically handle them. Whether Apple will ever reverse this limitation is unknown, but for now, Intel-based Macs are the only option for macOS eGPU setups.
4
Use a Thunderbolt Dock to Replace Your Entire Desktop Setup
Wouldn’t it be nice if you could come home, plug a single cable into your laptop, and suddenly have a whole desktop setup ready to go? While you can use a USB-C port in the same way, Thunderbolt generally has more bandwidth, allowing high-resolution screens and higher refresh rates, not to mention fast external storage. Of course, you can also make an eGPU part of this overall setup.
In fact, many of the nicer eGPU enclosures double as docks, so you can charge your laptop, and leave a mouse, keyboard, monitor, and speakers connected to it. So you really have a one-cable solution to switching between computing on the go and at your desk.
3
Boot a Mac (or PC) From an External Thunderbolt SSD
While it’s not quite as fast as the fastest internal SSD speeds, there’s more than enough bandwidth in a Thunderbolt connection to use an external drive as a boot drive and run your operating system from it. Even Macs support booting macOS from an external drive!
But, why do this? There are plenty of reasons to use an external boot disk, particularly if you’re using a laptop or mini PC that doesn’t have extra slots for more storage. It’s great for testing out Beta versions of macOS, and you can boot into alternative operating systems like Linux without making any permanent hardware changes to your PC.
Of course, you can do this with any old external drive over USB, even mechanical drives. What Thunderbolt brings to the table is speed, and the ability to use an external drive that feels like it’s an internal unit.
2
Create a Full PCIe Expansion Chassis
You can use all sorts of PCIe cards with Thunderbolt, not just eGPU setups. All you need is some sort of Thunderbolt PCIe expansion chassis, and you can make use of bandwidth-hungry cards such as video capture, broadcast controllers, high-end sound cards, and pretty much anything you can get drivers for.
For example, there’s the Sonnet Echo III rackmount case, which lets you connect up to three non-GPU PCIe cards to a computer with Thunderbolt 3 or later. This is the sort of thing that makes the latest Apple Silicon Mac Pro pointless, because the only real advantage it has over a similarly specced Mac Studio are those PCIe slots. Well, with an expansion chassis like this that becomes irrelevant, and the same is true for anyone on similar form-factor PCs or laptops.
The best part of this solution is that it lets you share hardware between different people. For example, if you had a studio mixing desk, each audio engineer can bring their own laptop and simply plug in to use the expansion cards. This way, if people are taking turns at a desk, it means you only have to buy one set of peripherals.
1
Turn a Laptop Into a Multi-GPU Workstation
A stack of GPUs for crypto mining
Not every GPU workload is bandwidth-dependent in the way that, for example, playing a video game is. There are some workloads that largely happen on the GPU itself. In other words, once the data is loaded into VRAM, the GPU doesn’t have to send much over the PCIe bus while it crunches the numbers. This includes running AI models, doing the training for those AI models, and professional workloads that can be split among GPUs.
This is why you can still buy multi-GPU workstations, because these jobs go faster if you can have multiple GPUs working on the problem. It turns out, you can connect multiple GPUs to a computer over Thunderbolt. For example, a blender artist connected three eGPUs to their laptop, by using a Thunderbolt 4 hub. Using this somewhat goofy setup with software that can split work between GPUs, they saw a significant improvement in performance.
This is definitely a very niche use case and likely buggy as all heck, but it’s kind of awesome that your laptop can moonlight as a GPU render farm at night, assuming that the cost of the hub and enclosures aren’t unreasonable.
Considering that Thunderbolt 5 offers up to 120Gbps of bandwidth in its special “boost” mode—and that number will only go up in the future—I expect to see more and more external versions of hardware that you would usually only consider in internal, directly-connected form.
The ultimate solution may not be Thunderbolt in particular, but as the desktop form factor continues to decline, fast peripheral connection standards will be crucial to keeping your options open.