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What's the difference between USB-C and Thunderbolt 3?

With more and more manufacturers opting to include USB-C and Thunderbolt 3 ports on their laptops and other devices, many people are wondering exactly how these ports differ and what the terms actually mean. To help explain how the two technologies work, let's take a quick look at the history of each, and how they apply to our devices today.

What are the different types of USB?

The numbered designations of USB cables are revisions that have been made over the years. USB 1.1 was the first commercially available, USB 2.0 came a couple of years later, and we've since moved into USB 3.0, USB 3.1 Generation 1, and USB 3.1 Generation 2. Both generations of USB 3.1 might be called SuperSpeed, but their speeds are 5Gbps and 10Gbps respectively.

Each revisions upped the speed of data transfer, as well as the amount of power that could be delivered. With these revisions have also come some different shapes of connector and port. New revisions have remained backward compatible with older technology, albeit with the use of adapters, hubs, and dongles.

USB-A

USB-A on top, USB-C below.

USB-A, also known as USB Standard-A or USB Type-A, is a rectangular connector and has been around from the start as USB moved through the numbered specifications. USB-A ports are found on countless devices, including many desktop PCs and laptops. Your keyboard and mouse probably use USB-A to connect.

USB-B

USB Micro-B

USB Micro-B with SuperSpeed.

USB-B, also known as USB Standard-B and USB Type-B, is a more squared connector with beveled edges at the top, and it is compatible with USB 1.1, USB 2.0, USB 3.0, and USB 3.1. While nearly every computer over the past decade has been equipped with USB-A ports, practically everything that you would plug the other end of that USB cable into sported one of the various types of USB-B ports. The vast majority of printers and scanners even today are equipped with the original style of USB-B, which is nearly square. Most non-iPhone smartphones up until the past two years were equipped with USB Micro-B (more commonly known as Micro-USB), while a smattering of devices are equipped with USB Mini-B ports (like all but the most recent GoPro cameras).

USB-C

USB-C, also known as USB Type-C, signifies the shape of the connector and port that is the latest evolution in the line of USB-A and USB-B. USB-C uses a small, rectangular connector with rounded edges that can be inserted into a port facing up or facing down.

USB-C connector.

As for the specification, USB-C is most commonly USB 3.1, which is capable of delivering up to 10Gbps transfer speeds. It can also deliver up to 100 watts of power — enough to rapidly charge even a high-power laptop. Do you have a phone that uses a USB-C port? What about a laptop? The Lumia 950 and ASUS ZenBook 3 are both examples of devices that use USB-C to both charge and transfer data.

What is Thunderbolt?

Thunderbolt, like USB, has gone through a few revisions before arriving at the latest, Thunderbolt 3. The original Thunderbolt had a top speed of 10Gbps, Thunderbolt 2 had a top speed of 20Gbps, and Thunderbolt 3 now has a top speed of 40Gbps. While the first two Thunderbolt revisions used a Mini DisplayPort connector and port, Thunderbolt 3 has teamed up with USB-C.

Think of Thunderbolt 3 as borrowing someone else's car — in this case, a USB-C car — and being able to drive it very quickly. When that speedster isn't driving the car, speeds return to normal.

USB-C with Thunderbolt 3

The lightning bolt next to the USB-C port signifies that it is Thunderbolt 3 capable.

Thunderbolt 3 cables can work as regular USB-C cables, and vice versa. However, the port on your device must have a Thunderbolt 3 chip in order to take advantage of the extra speeds. For example, plugging a USB-C cable into a regular USB-C port and expecting Thunderbolt 3 features will leave you sad.

Why do we want Thunderbolt 3? Well, it's four times faster than the top 10Gbps speed of USB 3.1, plus you can have up to eight lanes of DisplayPort 1.2 data going back and forth, as well as four lanes of PCIe Generation 3 going back and forth.

Have you seen those external GPUs some new laptops use? They're most likely connecting through a USB-C port that is Thunderbolt 3 enabled, taking advantage of the PCIe lanes. Have you seen multiple external monitors connected to the same laptop with a single cable? They could be using the DisplayPort lanes granted with Thunderbolt 3.

TL;DR

USB-C is a relatively new USB connector that can deliver up to a 10Gbps transfer speed and up to 100 watts of power. It's also fully reversible — nor more worrying about plugging it in the right way.

Thunderbolt 3 is a completely different technology that uses USB-C connectors and ports. With Thunderbolt 3, you can expect speeds up to 40Gbps, as well as multiple PCIe and DisplayPort lanes for connecting things like external GPUs and multiple, high-res external monitors through a single cable.

Have more questions? Be sure to drop them in the comments section.

Cale Hunt
Cale Hunt

Cale Hunt is a Senior Editor at Windows Central. He focuses mainly on laptop reviews, news, and accessory coverage. He is an avid PC gamer and multi-platform user, and spends most of his time either tinkering with or writing about tech.

45 Comments
  • Nice article, and it helps me understand a little more. However, what was missing is information like, "Dell uses x". "Microsoft uses X". I have an understanding of the definition of the connectors, but no real understanding of if one is an industry standard today, or the future. thanks
  • They are all industry standard. Some Dells (XPS 13 and 15) have Type-A and Type-C, but the Type-C is only two lane rather than four so it cannot support external graphics cards at full speed. Microsoft uses Type-A, and not Type-C. Really, Type-C is not all that important right now. Sure, you can power your device using it but you still need to carry around a power brick. Not all Type-C power bricks are powerful enough. For example I have the Apple Type-C charger, it is powerful enough to charge my XPS 13, but not my XPS 15. I have the Google ChromeBook Type-C charger, and it is powerful enough to charge my 950XL, but not my XPS devices. There are relatively few devices out there that have a Type-C port, and if you can find one it is generally more expensive. So while there are laptops with the port, the only real use there is right now is if you buy a Type-C to Type-A or Type-B cable to connect your existing devices. I did find a external enclosure that I put an SSD into that has a Type-C port, but you don't get faster speeds than using a Type-A or Type-B connection. In other words, right now Type-C is overhyped. 2 or 3 years from now there may be better support, but now it is one of those things that people like to use to start arguments for the sake of starting an argument.
  • This is the absolute best comment I have ever read from you.
  • My L950 is a USB 3.1 but what I wanna know is, is it gen 1 or gen 2? What are the physical differences between Gen 1 and Gen 2?
  • Couldn't agree more, not all USB-C is the same. My GF has an Apple laptop with USB-C but lost the power adapter so she bought a replacement from targus for $20 it charges her laptop fine but one morning my Idol 4s was getting low on battery so I decided to try to charge it with the laptop adapter and the phone would not charge. I thought maybe it delivered too much power since it is specced for up to 45W but a similar adapter from a friend's HP laptop was able to charge my phone.
  • The article is okay, but the pictures are a problem. For example: the pic right below USB-B does not show a USB-B plug at all. Instead, it shows a Micro USB-B 3.1, which is a completely different plug.
  • Agreed.
    I only very recently got my head around it all but I found these pics confusing. I stopped reading the article so I didn't get mixed up again.
  • I think this will clear up a few misconceptions. Good article. A+++ Would read again!
  • Okay, clarify for me if you can: Speed aside, are all USB-C ports Thunderbolt 3 compatible?  Are all Thunderbolt 3 ports USB-C compatible?
  • All Thunderbolt ports are USB-C, but not all USB-C are thunderbolt. All squares are rectangles. Not all rectangles are squares.
  • You can tell by the way it is.
  • Thunderbolt 3*
  • enlightening article. good job
  • The article does not mention if for power purposes they are interchangeable. Will I fry my L950/950xl if I use one of those laptop's chargers?
  • You can use any usb-c charger for your phone.
  • Only if the manufacturer A doesn't follow the usb-c 3.1 gen 2 specs, then product B can get fried.
  • Like the dash charger for the one plus 3
  • Its works great with my 950 XL.
  • Shouldn't normally be a problem. Your device will always only request as much power as it supports, so even chagers with QuickCharge mechanic won't fry your device. Only very cheap third party chargers might be a potential issue, if they are not built right (same goes for cheap cables sometimes).   But it is possible that some chargers won't fully work on another USB-C device and only charge slowly (even if the device would support QuickCharge) but generally, it all should charge with no issue. Samsung Galaxy S8 charger works on the Nintendo Switch and vice versa for expample.
  • USB-C 3.1 gen 2 should have been named USB-C 3.2. It is confusing to the consumer.
  • So thunderbolt 3 is a faster usb c, but then why use a usb c when you can use a faster cable? Unless I'm missing something. Do they work the same or function differently?
  • So thunderbolt 3 is a faster usb c, but then why use a usb c when you can use a faster cable? Unless I'm missing something. Do they work the same or function differently?
  • NO. Thunderbolt is a protocol that can work through usb-c. Usb-c is only a connector (to simplify) and it can support thunderbolt or usb3.1/3.0/2.0/1.1 it doesn't automatically guarantee high speeds
  • If the port is not thunderbolt 3 the cable won't change anything.... All USB-C port are not thunderbolt 3.... A little like HDMi port that look all the same but some are not 4k HDR ready.... Having a 4k HDMI cable won't help
  • Can Thunderbolt 3 project to 4K monitors? Does it have any PCIe/display port limitations?
  • A full thunderbolt 3 connection can display to 2 4K monitors at 60 HZ. Or 1 8K monitor at 60 Hz.
  • Good article. Seems to me, for now, Microsoft was wise to hold off on a USB-C on their Surfaces. (I recall also some confusion on which cables did what). Or am I missing something?
  • Great article. Thunderbolt 3, or the lack there of, is the reason why the new Surface Pro just isn't worth the upgrade to my Surface Pro 2. Without that port, the Surface Pro just isn't future proof enough for me, especially as I'll be grabbing the top of the line version.
  • Very helpful article, thank you!
  • Question? If i have a slim powerful laptop like an i7, 16GB surface pro or dell xps and let's just say for the argument sake it had a thunderbolt port. If i then connect it to one of those external GPUs, can i now play games on full resolutions with no problems (i.e. Lag or overheating)?
  • For sure, so long as the CPU nor GPU become a bottleneck for the game configuration.
  • Nah, ram, buses and termal throttling would likely keep the performance down
  • This article would have been better with pictures.
  • "The article does not mention if for power purposes they are interchangeable. Will I fry my L950/950xl if I use one of those laptop's chargers?" Well I said it because once I was stranded with a low battery in an apple store and i used one of the thunderbolt chargers of one of those laptops in display. It reported a whopping 150% and 400%/hour charge but I felt something was gonna give... It charged it fast though.
  • Nice and informative article, thanks. Maybe it had some points missing according to readers but it is not possible to cover everything to everyones liking. It was consise and to the point.
  • There's some problems in this article... Like USB-C is just a type of port, its not bound to any version of USB and any version can use it. The version itself determines the speed, thus USB-C isn't always 10 Gbps. The 100W of power thing is also a separate standard and despite what so many people seem to think these days, its not always gonna come with USB-C. I think its because of these misconceptions that its so slow to be adopted, especially on desktop PCs where its motherboards that have more than one USB-C port is rarer than hen's teeth.
  • Thank you! It all makes sense now. :)
  • TL;DR: Thunderbolt 3 is USB Type C.
    USB Type C isn't Thunderbolt 3 necessarily.
  • Awesome article, thanks! I didn't even know about Thunderbolt.
  • <p>I would like to see a list of all&nbsp; major PCs (and Windows and Android phones) that has USB-C ports, with indication of whether it (they) can be used for charging (with Watt capacity) and Thunderbolt 3 data/video transfer.</p>
  • You forgot the performance laptop users (Lenovo P50, P51, Dell 7710, 7720 etc.) TB 3.0 doc can't give enough power to these devices. If you switch from traditional doc to TB 3.0 you will need two power adapters instead of one. One for TB 3.0 doc and second for the laptop. Result is more spagehtti on you desk and you have to connect two cables when leaving or coming to workplace. TB 3.0 drivers and support other than Intel GPU may give some headache.
  • Interesting
  • Very useful info.
  • Thank you for this information.
  • Great info. But judging on the comment section I should look more into this myself. Thank you, none the less :)