Understanding the Difference Between Mac USB and Thunderbolt Ports

It is easy to be confused by the different types of ports on Maca, especially then names like USB and Thunderbolt are sometimes uses interchangably. Learn the differences between these kinds of ports and how to avoid confusion when talking about them.

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Video Transcript: Hi, this is Gary with MacMost.com. Today let's take a look at different types of Mac USB and Thunderbolt ports.
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So I often get questions about the different types of ports that come on Macs. You've got USB ports but there are different types of USB ports. Like USB-A or USB-C. You also have Thunderbolt ports but Thunderbolt 1 and 2 ports look different than Thunderbolt 3 ports. Sometimes a port is called USB and sometimes it's called Thunderbolt. So which is it? So let's take a closer look at the different types of ports and try to unravel the mystery.
So there are 3 main types of physical ports that we'll be talking about. Here's one and it's usually just called a USB port. It has looked the same for more than two decades. You're probably familiar with it. It can do all sorts of things. You can use it to hookup and keyboard or mouse to your computer. You can also hookup various types of drives including the little flash drives. You can power devices. For instance you can charge your iPhone from this port. You can even power little gadget. Sometimes those little LED flashlights or even fans and all sorts of things that can be powered with a USB port like this. You could hookup tons of computer peripherals like a printer, scanner, webcams. All sort of things use this. After all the U in USB stands for Universal. So it can be used for lots of different purposes.
Now if you have an older Mac, even one that's just a few years old, you may have a port that looks like this. It's a Thunderbolt port. But technically it's Thunderbolt 1 or 2. But also sometimes a port that looks exactly like this isn't a Thunderbolt port at all. Sometimes it's something called a Mini Display port. We'll talk about that in a minute.
A basic Thunderbolt port or a Mini Display port can be used to connect an external screen to your Mac. You can even get an adapter for it that will go and hookup an HDMI television to your Mac. You can also use Thunderbolt to hookup external storage like an external hard drive although Thunderbolt drives are harder to find than USB drives. You can do a variety of other things with it. For instance you can get an external graphics processing unit to increase the graphics performance of your Mac. You can hookup video capture devices. You can even hookup an adapter to allow you to connect over ethernet to a network. There are also docks that you can get for Thunderbolt ports that take the Thunderbolt port and then give you things like several USB ports, maybe HDMI, maybe a SD Card reader. All sorts of things like that.
Now if you have a newer Mac you don't have either of these ports. You have a port that looks like this and takes cables that look like this. These are USB-C ports. So it gets confusing because this will be referred to as a USB port just like the USB-A port. But the shape is clearly different. To make it even more confusing this is often referred to as a Thunderbolt 3 port. We'll take a look at why both names are actually correct. In addition to doing all the other things that a Thunderbolt 1 or 2 port could do, you can also use this to power your Mac. So the power into your Mac can go through this USB-C port.But you can also use this to connect older USB devices. Ones that require the USB-A port. You can just get a simple adapter for those.
So the real reason for a lot of confusion about these ports is the fact that when you talk about something like USB or Thunderbolt you're actually talking about two different things. You're talking first about the physical port itself. Second about the type of connection. The language that is being spoken between your computer and whatever is connected to it.
First looking at Physical Ports we can see there's the USB-A port. There's also something called a USB-B port. You won't find that on a Mac but usually you'll find it on peripherals like a printer or a scanner. It will have a port like this. So you have a cable that on one end is USB-A and the other is USB-B. Now the newer type of port is USB-C. It's a little smaller and most importantly it's bidirectional. In other words you can plug it in either way. USB-A ports you had to plug it in a certain way and if you plugged it in the wrong way you had to go in and you had to turn the cable around to make it fit in. With USB-C it doesn't matter.
Now a fourth type of port is a Thunderbolt 1 or 2 port. As I said before this is also the same physical shape as a Mini Display Port Connector.
So now  let's look at connection types. You can see we're going to use the same names here which is why it gets very confusing. So have you various type of USB connections. The original connection just called USB or USB-1 was actually very slow and wasn't very good for data transfer. It was fine for hooking up things like keyboards and mice. USB-2 made things a little bit faster and now we've started to be able to use things like little flash drives as storage devices. But USB-3 really pushed the speed limit up. Now we can actually have fast transfer and use USB for storage. There are two flavors of USB-3. USB 3.1 Gen 1 and USB 3.1 Gen 2. Gen-2 simple increased the speed. Now note that everything is backwards compatible. So if you have a port on your Mac that's USB 3.1 Gen 2 it can connect to any device that's Gen 1. USB 2 or original USB-1  
Now Thunderbolt connections also have three different generations. Each one varies by speed. So Thunderbolt 1 was only 10 Gbps. That doubled for Thunderbolt 2 and then doubled again for Thunderbolt 3. So if we put these two tables side-by-side we can see how's there is confusion. Because when you say you're connecting something using USB or Thunderbolt what do you really mean? If you want to be really accurate you should actually talk about both the port and the connection type. 
So, for instance, you may say I'm using USB-A to connect a USB 3.1 device. Or I'm using a Thunderbolt 2 port to connect to Thunderbolt 2 device. Including both eliminates any of the confusion. So if you have an older Mac, say about 5 years old, this is what you may have. You may have USB-A ports and also Thunderbolt 2 ports. Now what can you do with those. Well, the USB-A port can be  used to connect to any USB 3.1 device and also backwards compatible with USB 2 or USB. The Thunderbolt port can be used to connect to any Thunderbolt 2 device and also backwards compatible to Thunderbolt 1.
Now if you have a much older Mac I should point out that instead of having a Thunderbolt 1 or 2 port you may just have a Mini Display Port. Apple produced these for a couple of years. So you can't hookup any Thunderbolt devices at all. But you can hookup a screen using the Display port. The screen can either have a Mini Display Port connector or a Display Port connector. One is just bigger than the other. But it doesn't matter as long as you have the right cable. So Mini Display Port on your Mac to regular size Display Port on your screen is just a matter of having that particular cable.
Now if we go with a modern Mac we can see we've eliminated USB-A port and we've eliminated the old style Thunderbolt port. Instead we have just one type of port. A USB-C port. This can connect to USB 3.1 or backwards compatible with all of the previous versions of USB. It can also connect to Thunderbolt 3, and Thunderbolt 2, and Thunderbolt 1, and also I should point out the Mini Display Port.
So the way to think about this is think about the ports as people. People would have a nationality, say if somebody was from France. Now you would assume that somebody from France would speak French. But, in fact, they might actually speak more languages than that. So, for instance, this person is French but they speak both French and English. Now if you have another person and they only speak English and if the two of them were to talk they would be talking in, of course, English. So let's turn these people into ports. Let's say the first person is a USB-C port and that's your computer. The second person is a device that you're going to connect to it. That has a USB-A port. So since the first person is USB-C they can speak both USB 3.1 and Thunderbolt 3. But the peripheral is just a USB peripheral. It just speaks USB 3.1. So when you connect the two with a cable they are going to talk to each other using USB 3.1
What about if it's an older device? A USB 2 device. Well, fortunately USB 3.1 is backwards compatible. So now the device that only speaks USB 2 can talk just fine to the computer because it's backwards compatible. Likewise if the device is a Thunderbolt 3 device and you connect it to the very same computer instead of speaking USB 3 to each other they are going to speak Thunderbolt 3. If the device is older and is USB 2 they would both talk USB 2.
So let's look at some examples. Let's go back ten years to a 15 inch MacBook Pro from 2010. Now this device has lots of different ports on it. It has some USB-A ports on it. I has an analog port from hookup headphones. It has a dedicated power port that can only be used to plug power into the laptop and it has a special port, a Mini Display port that can be used to connect an external screen. That's all it can be used for. It looks like a Thunderbolt 1 or 2 port but it's not. It can only be used to connect a screen and speak Mini Display Port to that screen.
Now let's go forward 5 years. We still have USB-A ports and we still have analog audio and we still have a dedicated power port. But now, instead of a Mini Display Port, we've got a Thunderbolt 2 port which is great because not only can this port talk Display Port and be used to connect a screen but could also talk to Thunderbolt 1 and 2 devices. This port, even though it looks the same, is much more useful.
Now let's go forward to today. You get a MacBook Pro today you're not going to have any USB-A ports on it. You're not going to have a dedicated power port on it either. Instead you'll have a bunch of USB-C ports. These ports will be able to talk USB to any USB device, be able to talk to Thunderbolt to any Thunderbolt device, and also Display Port to any Display Port device. Not only that it will be able to accept power into the laptop. So you can use anyone of these ports to plug in your power adapter. 
So what you have now is a lot of versatility. One person may use the USB-C ports on their Mac one way, say connecting one to power, another one to a SD card reader, maybe a camera is connected to a third one, and a printer to a fourth one. Another person may decide to actually  have power in one and two screens connected to two of the other ports. 
One of the problems from upgrading to a Mac that uses USB-A ports to one that uses C ports is you may have a bunch of USB devices that use USB-A. Fortunately you can easily adapt these to USB-C. Apple sells a connector for $20 that has a short length of cable. But you can get for a few dollars little adapters that look like this the you can put on the end of your USB-A cables to convert those ends to USB-C. You can usually get these in packs of two, three, or even more pretty cheap. Another option is to simply replace the cable. Now if you have something like a flash drive then USB-A connector is built right into it. Right. There are also various devices where the wire is actually hardwired into the device so you can't just swap out the cable. But if you have a device like a printer or scanner or something that has a cable that can be removed you can simply replace the cable instead of USB-A to USB-B to connect a printer just buy a new cable, USB-C to USB-B. 
Already some devices are shipping with both kinds of cables. For instance I recently bought an external drive that actually had one cable that was USB-C and another cable that was USB-A. You just chose the one that worked for the computer you had. So I hope this video helps you understand the different types of connections you may come across when using Macs. If you have any questions ask them in the Comments below.

Comments: 10 Responses to “Understanding the Difference Between Mac USB and Thunderbolt Ports”

Howard Brazee

3 weeks ago

My wife has a 2017 iMac, and I have an adaptor allowing her to connect to Thunderbolt-1 devices. But I haven’t found an adapter that allows my 2013 iMac to connect to Thunderbolt-3 devices. I do have a SSD that comes with USB and Thunderbolt cables.

(I am planning on buying a ARM iMac after one 32-bit program gets updated—we’ll see which comes first)

Gary Rosenzweig

Howard: You can’t connect a Thunderbolt 2 Mac to a Thunderbolt 3 device. The Mac was built before Thunderbolt 3 existed and it simply isn’t compatible with it.

Dana Stevens

Gary, I have a Mac mini (Late 2014) with Thunderbolt 2 ports connected to an OWC Thunderbolt 3 Dock using a Thunderbolt 2 cable with an Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter. The Thunderbolt 3 Dock works fine. Apple says about the adapter “As a bidirectional adapter, it can also connect new Thunderbolt 3 devices to a Mac with a Thunderbolt or Thunderbolt 2 port and macOS Sierra or later.” This seems to say that older Macs should be able to connect to Thunderbolt 3 devices.

Dana: So that Dock is a Thunderbolt 1/2/3 device. That would work fine, but at Thunderbolt 2 speeds. But if it were a Thunderbolt 3-only device, it wouldn’t work.

Cameron C. Cook

I have a new Macbook Pro with USB-C ports. I’m looking to buy an external hard drive. My question is whether I should look for a USB-C drive if it is a non solid state drive? I can see when using an SSD drive USB-C would be preferable but a regular drive is much slower so would there be any benefit to USB-C?

Cameron: Spinning drives have two advantages over SSDs: price and size. This makes them ideal for things like backups or storing archives of old projects and such. So it still makes sense to get spinning drives that are USB 3.1 (the port type is irrelevant) in those cases.

Laverne LaChapelle

No question; just a thanks. Terrific video setting out all the various “flavors” of cables and how they work together.

Will

Great Video. I expect to refer back to it several times.

Lencho Cazador

Is there a reason you skipped covering quality issues? Especially Apple MFI Certified. Excellent info at paracable.com. Is this no longer an issue? It seems that with the increases of speed and, especially power, quality becomes ever more important. A melted cable could ruin someone’s entire day.

Lencho: A discussion on quality isn’t what I was going for here — but an understanding of the types of ports and cables. The best USB cable in the world doesn’t help if what you need is Thunderbolt, etc.

Understanding the Difference Between Mac USB and Thunderbolt Ports

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