Thunderbolt Road

How Thunderbolt, the ultra-fast connector that recently turned 10, started life with a completely different look. (Fun fact: $400 Thunderbolt 3 cables exist.)

Today in Tedium: Two decades ago, the fastest data connection that we could hope for from a standard personal computer was 1 gigabit (125 megabytes) per second in speed, first brought to the broader computing world in the year 2000 by the Power Mac G4 and the PowerBook G4. USB (at first) was slow; Firewire (at first) was fast, but it was less than a third of the speed of Gigabit Ethernet. These days, the current speed champion is Thunderbolt, which saw its fourth iteration released last fall and celebrated its tenth anniversary of release late last month. Like its predecessor Thunderbolt 3, Thunderbolt 4 can do 40 gigabits (5,000 megabytes) per second … if you have the right cable. It’s something best known as an Intel creation—the chipmaker owns the trademark and is very protective of how it’s used. But the story of this magical connection hiding in many USB-C ports took a weird detour in the press before we got what we have today. Today’s Tedium takes a look at the evolution of Thunderbolt, checks out a cool dock, and explains why the cables are so dang short. — Ernie @ Tedium

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“Thunderbolt is a revolutionary new I/O technology that delivers an amazing 10 gigabits per second and can support every important I/O standard which is ideal for the new MacBook Pro.”

— Apple Senior Vice President of Marketing Phil Schiller, announcing the initial release of the Thunderbolt technology in a press release on February 24, 2011, as part of an upgrade to the company’s MacBook Pro line. That’s right, guys—Thunderbolt was not deemed a cool enough technology for a Steve Jobs keynote at a time he was still with the company. Perhaps it’s because the prior keynote involving the technology might have upstaged anything Apple could have hoped to do with it.

Thunderbolt Ports

Thunderbolt on a 2013 MacBook Pro. Originally, Thunderbolt ports weren’t supposed to look quite like this. (Kārlis Dambrāns/Flickr)

The inside baseball that made Thunderbolt’s initial launch extremely fascinating

The story of Thunderbolt is really about two separate technologies—the highly experimental, futuristic one that showed up in early keynotes, and the more ho-hum one that, while sporting many of the same elements, wasn’t even enough to get Steve Jobs to the stage.

And perhaps the differentiating factor comes down to what was hiding in the wires in the end. See, the technology that became Thunderbolt was sold to the world as a way to “bring optical connections to the mainstream,” the centerpiece of a 2009 keynote at the Intel Developer Forum.

And at the time it was announced, it sort of felt like it came out of nowhere. This was peak Intel, years before the company got caught up in debates about cores and fabrication processes, releasing a new technology on the world that promised to do something truly unique and innovative—a 10-gigabit connection that worked over fiber optics, rather than the copper wires we were used to.

To reflect this, the technology was given a suitably optical name: Light Peak.

Light Peak

A press photo that Intel offered circa 2009 highlighting the functionality of Light Peak.

Intel’s blog post, fittingly written by a guy named Benjamin Hacker, was suitably breathless:

Once relegated only to datacenter and telecom environments with high price points, optical technology may soon find its way into mainstream client systems, consumer electronics, and even handhelds. A new technology was announced at Intel Developer Forum (IDF) which provides initial data rates of 10 Gigabits and potential scalability to 100 Gigabits and beyond; something copper IO won’t be able to achieve.

Light Peak also supports multiple simultaneous protocols which will allow bandwidth aggregation of the various interconnects used in systems today onto a single high speed, thin, flexible, and long cable and small connector. Imagine being able to connect to your camera, display, docking station, or external hard drive through a single, thin connector!

And honestly, it was easy to get caught up in the hype. Just check out this video of Intel engineers showing off how they managed to shrink fiber-optic conversion technology miniaturized to something about the size of a USB port:

As technologies go, this was explosively awesome! This was going to destroy USB in a way Firewire never could!

But we ultimately did not get Light Peak in its original form. Nor did the technology that Light Peak became, Thunderbolt, really set the world ablaze. It landed in laptops a couple of years later, largely still using copper.

So what happened? Well, according to an early report about it from Engadget, Apple essentially offered up the concept of Light Peak on a platter for Intel to create and show off as their own technology.

Engadget Light Peak

An Engadget screen shot showing off the Hackintosh used to demo Light Peak.

The Engadget team, from the era just before they moved over to The Verge, got curious about the endeavor after noticing that Intel appeared to be demoing Light Peak on what looked like a Hackintosh. And it turned out there was fire under that smoke.

“While the timing doesn’t line up, a low-powered Light Peak sounds like the kind of technology that would be perfect for a device with a need for broad connectivity but limited real estate for ports … like a tablet,” Joshua Topolsky optimistically wrote of the rumors, hinting of the iPad coming the next year (without the optical connection, alas).

So what was displayed was a clearly early demo of something not really ready, that aimed to build excitement around it. And after more testing, Intel engineers ultimately came to the conclusion that they could do pretty much everything they wanted to do with Light Peak … using boring old, cost-effective copper.

“The copper came out very good, surprisingly better than what we thought,” the company’s David Perlmutter told Computerworld. “Optical is always a new technology which is more expensive.”

The truth is, while fiber optics are certainly much more flashy (who doesn’t love a stock photo of torn-open optical cable with fancy lights reflected on it?), copper and optical technologies have tradeoffs when it comes to Thunderbolt. Optical cables can run for distances as far away as 100 meters … but they cannot carry power, and they’re not cheap. And copper can carry power as well as the full promised speeds of Light Peak … but the cables can only be so long.

When Thunderbolt first appeared on a MacBook Pro in early 2011, it showed up using a port that already existed on a prior version of the laptop—a MiniDisplayPort socket. It was not optical, but it was still pretty fast, combining both the ability to push around DisplayPort and PCI Express signals.

And quickly, Thunderbolt gained a reputation not as a potential replacement for USB, but as a high-end option for mostly Mac users in need of an ultra-fast connection on their machines. It was a reputation not helped by the device’s aggressive use in the 2013 Mac Pro, which featured six of these ports.

By downplaying Thunderbolt at first, Apple perhaps tamped down expectations for the rest of the industry, which largely ignored the new technology in favor of USB 3.0, which was far slower than Thunderbolt but also backwards compatible with the billions of devices put out into the world with USB-A ports.

In the long run, however, Thunderbolt eventually would need no tamping down among professional users. For one thing, it could do significantly more more, allowing (for example) full-speed ethernet connections, as well as the ability to plug in monitors and, at a technical level, anything with a PCI Express (PCIe) computer standard. If you had the right enclosure, you could run a GPU … or a hard drive bay.

Also helping: Intel kept at it, improving the technology to the point where it was pretty good and, when the opportunity showed itself, switching ports to something more commonly used—which is why Thunderbolt looks so much like USB-C in the modern day, for better or worse.

“USB connectors are not general purpose connectors and are not designed to be used in support of other technology applications or standards or as combo connectors. The unauthorized use of USB connectors and specifications may cause a variety of problems with interoperability, compatibility, usability, and may lead to hardware failures, consumer confusion as well as other legal and marketing issues.”

— The USB Implementers Forum, in a statement calling out Sony’s then-subsidiary Vaio for creating a USB port with additional Light Peak-based optical connection technology to help power a GPU for its laptop. This quirk in the history of Thunderbolt is interesting for a few reasons: One, Sony released the device after Intel had made MiniDisplayPort the standard Thunderbolt port; two, the port stuck with the original optical approach of Thunderbolt; and three, USB and Thunderbolt 3 ended up merging together less than five years later anyway.

Thunderbolt 3 Pro Dock

What I learned about Thunderbolt from testing out a high-end Thunderbolt dock

Thunderbolt has been around a long time at this point, but with people remote for the first time, I wonder if a lot of folks are in the same boat as me: Suddenly interested in whether they should invest in it for their home office.

In that spirit, I personally just got my hands on my first device—a unit that was sent in for review by Other World Computing for my MacBook Air M1. (This is that review—standard mumbo jumbo about them not seeing my opinion on it before publishing it out into the world.)

Until now, I had mostly stuck with USB-C hubs and docks for compatibility and cost reasons, but decided to give the Thunderbolt 3 Pro Dock a swing, and I honestly get the appeal of a device like this, which solves most of my frustrations with traditional USB-C docks … even if it has a few things I don’t really need.

No knock on the dock itself. The device (clocking in at $299) is hefty, and not designed for moving around, complete with a power brick significantly larger than the one the MacBook Air itself uses. (OWC sells lower-end options, including a more portable mini dock with HDMI ports and a slightly cheaper option with more USB ports and audio output options.)

If there are any quibbles I have with port selection, it’s probably down to the decision to only include a DisplayPort rather than HDMI (or, preferably, both). While not the biggest issue in the world given the flexibility of the Thunderbolt spec, it’s sort of a headache for my use case, where I often swap between different port types during my day, with the DisplayPort already taken up by my desktop computer on my monitor. As HDMI tends to be more common with random devices, it would personally be more handy for me to plug in an HDMI port, rather than having to use up one of my USB-C ports for that purpose. But again, this is solved with a dongle.

I generally use one screen, but it’s a fairly large one, at 32 inches, and I frequently swap between devices (at this time, three separate computers). It has caused issues in the past in some contexts, because of its 4K resolution—on my Hackintosh, I had to mess around with Clover configurations to get it to work, and it straight-up didn’t work right with the low-powered Pinebook Pro.

But the biggest headache with the monitor comes from the bandwidth limitations of USB-C. Because of bandwidth, most USB-C docks do not support it in its standard 60Hz refresh rate over HDMI, clocking it down to 30Hz. So, until now, that meant I had to connect two cables into the Air to get a proper experience. But the OWC dock simplifies this, allowing me to leave a port open for other peripherals.

Probably my favorite feature of the Thunderbolt 3 Pro Dock is something that few dock-makers account for—a solution for the excessive heat these docks are famous for. USB-C hubs may have a lot of ports, but their headroom is limited, leading to situations where if you have too many things plugged in and too much data passing through, it might overheat and stop working—which has happened to me a few times with particularly large Zoom calls, where the video continues to display but I have no keyboard or mouse access.

Thunderbolt 3 pro dock rear

This dock contains a fan switch, a port for accepting SATA drives, and a power connector that fans of GPUs will love.

The Thunderbolt 3 Pro Dock handles this effectively through a combination of three features:

A massive power brick that’s nearly the size of the dock, and plugs in via a six-pin connector reminiscent of what you might plug into a graphics card.

A built-in fan. The fan is actually a great idea; it’s not super-loud, and additionally, it can be turned off for moments in which you need silence for things such as recording audio. (As I do the occasional podcast interview, this is a particularly helpful feature.)

A heatsink. The side of the box warns not to leave the fan off for extended periods, but from my experience, the big metal heatsink on the top effectively manages heat dissipation.

Why such a well-thought-out solution to heat? Easy, because this thing is intended to transfer lots of data. This device comes with some fairly exotic ports—a CFast 2.0 card slot, for those who prefer that faster memory card standard over the more common (and also included) SD Card slot, as well as an eSATA+ port, which allows for plugging in hard drive bays fairly easily. Both of these ports are fast—both capable of speeds similar to a 6Gbps SATA-based hard drive—but fairly rare outside of high-bandwidth editing settings. (On my end, the eSATA+ port will come in handy for flashing disk drives, while the CFast slot would be a great solution for a secondary drive for this device … if CFast cards didn’t cost so much.)

From a storage standpoint, OWC also offers creature comforts for making this device more usable, including a tool that allows users to unplug every storage device plugged into the dock at the same time.

With storage a focus, I did a little stress testing: I was able to burn an ISO of hello, the Mac-inspired iteration of FreeBSD I recently wrote about in MidRange, to an SD card at the same time as doing a Time Machine backup on an NVMe drive inside an enclosure connected to a USB 3.1 port, while also listening to a high-res audio stream over ethernet and connected to a 4K screen. If I did this combination of things with a USB-C dock, something would have slowed down, but the hub didn’t break a sweat.

Another area where this could come in handy is if you’re relying on high-speed ethernet to do data transfer; this has built-in 10-gigabit ethernet, which if you were running a big local network, this would be a huge productivity boon. The Intel Mac Minis support this, but if you’re for some reason stuck with the M1 version, this is a pretty decent way to get one, along with a bunch of other stuff.

This is a great device and will handle data transfer at the center of a hub admirably. Most of my quibbles with the way this device works, honestly, have more to do with MacOS’ handling of Thunderbolt on laptops, rather than of the device itself. As I said earlier, I tend to use one screen, and leave the laptop closed when set up in my hub. But to wake this device, I often find that I have to open up the laptop, then plug in the Thunderbolt cable, then wait a few seconds for my devices to wake. In comparison, plugging a USB-C hub and HDMI cable into the Air only takes a few seconds, and requires no opening of the lid.

I’ve heard that this may be a response to some security issues facing Thunderbolt, but it seems that the workaround involves plugging the computer in, then plugging in the Thunderbolt cable, which seems awkward, but works, apparently?

This awkwardness is all down to MacOS, ultimately. I went back to my old Spectre x360, which uses Thunderbolt 3, and ran my copy of Pop! OS on it. I found that, after I set it up to recognize the device, it connected flawlessly and allowed me to get straight to work. If you’re a Linux user, you will probably find the experience much more palatable than if you’re using MacOS and unplugging your laptop a few times a day.

Now, is this the right Thunderbolt dock for me? Perhaps not—I think the $50 cheaper OWC Thunderbolt 3 Dock, with more USB ports and built-in audio outputs, might make more sense for most people, as CFast and eSATA+ are pretty obscure outside of professional settings. But this is still an extremely useful device, and the built-in fan is an excellent way to avoid overheating issues when all of my stuff is plugged in.

(I kinda want the port selection of the cheaper device, but to keep the fan and heatsink on this.)


The cost of buying a 10-foot optical Thunderbolt 3 cable, produced by the glass company Corning, on Amazon. Optical cables are part of the Thunderbolt spec, but they are basically optional and don’t come with any of the power-charging capabilities the modern copper-based Thunderbolt cables do. (Those are running into price ceilings as well—Apple sells a high-end Thunderbolt cable for $129, with its differentiating factors being its length and ability to support DisplayPort despite its long length.)

Recently, Intel made a move that promises to turn Thunderbolt into the standard it did not become upon its initial public release a decade ago.

It essentially gave the specifications away to the USB Implementers Forum, allowing the faster Thunderbolt 3 standard to effectively become the basis for the new USB4 standard, which Apple Silicon devices now use.

But curiously, around the same time, Intel released the Thunderbolt 4 spec, which sounded a lot like Thunderbolt 3. Apparently, the big differentiator is that Intel means it this time.

“Thunderbolt 4 requires mandatory certification for all computers, which means Windows users finally get all the great features Apple users got with Thunderbolt 3,” tech writer Simon Jary wrote for Macworld UK back in January. “So Thunderbolt 4 standardizes Thunderbolt 3 for all computer users.”

In many ways, this is the problem that faces high-end ports like Thunderbolt—the desire to cut corners to save costs is pretty strong.

When you break it down, this is a pretty good reason why we didn’t get Light Peak in its original form. Sure, the copper works nearly as well. But we could have had fiber-optic wiring for our computers a decade ago … and likely for cost-saving reasons, we didn’t end up with that. It feels like a bummer in the end.

Let’s hope that, in the next decade, we finally take advantage of what this standard can offer, in the same way we did USB a couple decades prior.


Thanks again to OWC for supplying a Thunderbolt dock for review. Find this one an interesting read? Share it with a pal!

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