Thunderbolt 3 Delivers a Jolt

One thing that was clearly evident at NAB is that Thunderbolt 3 is the future. Or wait, USB-C 3.1 Gen 2 is the future. 

Before we get to that seeming contradiction (it mostly isn’t), let’s quickly review the history of personal computer connection technologies: parallel, serial, SCSI, USB, Firewire, Thunderbolt. All of those (and more) had multiple versions over time, some that were forwards and backwards compatible, some that weren’t. Apple tended to clearly use items that Windows machines didn’t, and vice versa, and moved faster through the ever changing connectivity landscape. All of which led to a lot of products being available only in one computer ecosystem, or requiring different handling or converters to be used in another. 

And if communication standards wasn’t confusing enough, we had different display standards, as well, with different cable options there, too.

Thunderbolt 3 tries to solve all that. It merges three things into a single cable: Thunderbolt, USB 3.1 Gen 2, and video display support. Pretty much anything you want to move from place A to place B will likely travel on Thunderbolt 3. 

Yet, there will still be great confusion even with a single standard. For instance, Thunderbolt 3 uses the current USB-C style connectors. The MacBook 12” has such a connector, though it isn’t Thunderbolt 3 enabled. Moreover, ask any two drive/storage/video vendors at the NAB show about “compatibility” between Thunderbolt 2 and Thunderbolt 3 and you’ll get five different answers. Truly. It seems that some booth personnel at the show haven’t gotten the Thunderbolt 3 indoctrination lecture yet. 

Thunderbolt 3 has three basic functions, as noted above:

  1. Implements Thunderbolt. Thunderbolt is a high bandwidth communication method and protocol. Thunderbolt 3 doubles the available bandwidth from Thunderbolt 2 to 40Gbps, though that’s broken down into directional channels, meaning that the fastest any given data piece travels from A to B is only 2.5Gbps. Still, that’s fast for data via cable, faster than we’ve had in the past; and some products might use multiple channels to achieve even faster speed.
  2. Implements USB. Everything you can do via USB—any variation—can be done over the Thunderbolt 3 cable. One of the more interesting aspects of this is power. Thunderbolt 3 enables 15 watts for bus-powered devices, and up to 100 watts for power charging. As with the MacBook 12”, most laptops will stop using a dedicated power cable, and most external devices you’d connect to the computer probably won’t need power cables, either. While the loss of a dedicated power cable simplifies things for laptop makers, it complicates things for the laptop user, as the MacBook 12” demonstrates: almost all of us have bought a dongle to plug into the USB-C connector on that computer to split signals out. The same thing is likely to happen with Thunderbolt 3.
  3. Implements Video. To be specific, DisplayPort 1.2 and HDMI 2.0 are directly supported. And there’s enough bandwidth for multiple displays to be active.

There’s even more to Thunderbolt 3 than those things, but those three items are the ones we’ll use the most, for sure. 

But here’s the problem and the reason why you couldn’t get clear answers to the compatibility issue at the NAB show: Thunderbolt 3 will need an adapter to allow you to plug in a Thunderbolt 2 device, and that adapter may be costly. It’s possible that some Thunderbolt 3 devices could be used on Thunderbolt 2 systems, but best case they’d only be serving Thunderbolt 2 capabilities (e.g. slower bandwidth, less power, and older USB/video standards). And again it probably will require an expensive adapter. 

Mac users have a bit of a problem at the moment, therefore. If you’re about to move to a Mac Pro (trash can style) or iMac Retina, you’re buying a computer with Thunderbolt 2 support. You’ll buy any of the current Thunderbolt 2 devices—of which there are many excellent ones—and you’ll be using the old style Thunderbolt cables. 

When Thunderbolt 3 hits—and I’m betting that the delay in updating the Mac Pro (trash can style) was partly due to this—you’re going to have issues with moving your Thunderbolt 2 drives and accessories to your new system. Just as we had issues with moving from Firewire, only this time it will be more costly now due to the expensive adapter that will be needed. 

On the Windows side you need to pay close attention, too. Acer, Asus, Dell, HP, and Lenovo all have Thunderbolt 3 capable laptop models on the market today, but they also have many more models that aren’t. Moreover, one of the big questions I kept hitting at the show was this: “who has a Thunderbolt 3 certified cable?” (Such a cable has the official Thunderbolt 3 logo on both connectors. Obviously, you could fake that and sell a cable that hasn’t yet been certified, which would cause confusion and problems, though you’d eventually be hit with a cease and desist order by the standards group.) 

So the good news is that we’re going to get a standard connection that Mac, Windows, Linux, plus specialty hardware companies like you find in the video business, will all be using. Finally. The bad news is that we’re still going to have a transition to go through, and it could be a bit of a rough one for some.

The question that comes up is this: should I wait to buy a system today? I would say yes if you were thinking about a Mac Pro. Not only will you get locked into a lot of Thunderbolt 2 gear, but you’re getting a box (can) that has slipped from a state-of-the-art (CPU, GPU) to start with. Some think that the about-to-be-announced next generation of MacBook Pros will be Thunderbolt 3, so if you’re in the market for a Macintosh laptop it might be wise to wait until June when those are announced to see if that’s true. 

There’s no reason for most of you to worry, though. If you’re just looking for a great system and are only going to hang a couple of big drives or RAIDs off of it, the difference between Thunderbolt 2 and 3 isn’t likely to come into play for you any time soon. You may even start finding Thunderbolt 2 devices coming down in price prior to the full transition to the new standard. 

But the big video rigs (Mac Pro) and the portable devices (MacBook Pro) might be a different story, depending upon how far you want to take them. The same is true on the Windows side, as well. Gigabyte is making the first desktop CPU boards with Thunderbolt 3, while the other Windows computer companies I mentioned all have at least one laptop/notebook computer with Thunderbolt 3 already. The Thunderbolt 3 floodgates are about to open.

OWC was displaying three of their products with Thunderbolt 3 at their NAB exhibit. LaCie was debuting their new 12Big with Thunderbolt 3, and was more illustrative of the way many will deal with the future: "For universal compatibility, users can connect to USB-C laptops—and even USB 3.0 computers via the included USB-C to USB-A cable.” In other words, the primary backwards compatibility with many of the Thunderbolt 3 products in the future will be USB-driven. 

So, one thing you’ll need to be aware of is the logo next to any USB-C port. Unfortunately, I don’t have the final logos available to me at this time, but here are the four significant variations for a USB-C port:

  • long established USB three wire logo: only USB 2.0 on connector
  • above + SS in front: USB 3.1 on connector at 5Gbs
  • above + 10 above the three wire bit: USB 3.1 on connector at 10Gbs
  • Thunderbolt insignia: Thunderbolt 3

There can also be a D next to it to indicate DisplayPort capability (assumed with Thunderbolt 3). And the logo can be in what looks like a battery, which indicates that the full power capability is there (15 watts external, 100 watts charge), also assumed with Thunderbolt 3.

Finally, one thing that a lot of people haven’t noted yet: Thunderbolt cable distances are highly limited, at least for wired cables, and it doesn’t matter which Thunderbolt we’re talking about. Thunderbolt 2 and 3 have a 3m limit (10’) to meet performance specifications. So what happens if you want to put your device further away? Well, you do what some of us have been doing with Thunderbolt 2: you buy an expensive fiber optics cable to extend the distance. Typically, these are Corning Optics cables, and they come in 18’ (6m), 33’ (10m), 98’ (30m), and 164’ (50m) lengths, and start at about US$180 (see below).


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