Thunderbolt 3 is inextricably linked to USB-C in terms of connector, but USB-C can also exist without Thunderbolt. USB 4 can also be part of USB-C. You cannot see from the outside what exactly is being supported. In short: what is the difference between USB-C and Thunderbolt?
usb-c is just about the standard on new digital hardware. You will find the flat connector with rounded corners on laptops, smartphones, tablets, portable gadgets and more. Finally something universal, you would say. But although usb-c seems like a standard, it is more of a ‘service platform’. Because usb-c is on the one hand usb 3.x, but can also be Thunderbolt at the same time. And Thunderbolt (3) is an even faster serial port that also thanks to that speed the PCI Express bus from the interior of your computer or device to the outside (there are cabinets available that ‘convert’ Thunderbolt 3 to pcie) slots where you can then, for example, insert a regular video card or something similar).
The problem is that you cannot tell from the connection whether it is only a USB 3.x-compatible connection, or whether Thunderbolt 3 is also part of the package. And to complicate matters further, there are also generations of USB-C that support different speeds of USB 3.x. One consolation: if you only want to connect an external hard drive, luckily the speed differences don’t make much difference. Certainly not with a mechanical hard disk.
Anyway: usb-c is the name of the mechanical connection, the underlying protocols supported vary.
Check the specs (preferably before purchasing)
Back to basic. How can you find out what the USB-C connection on your device can and cannot do? For that you really have to dive into the specs of your device, only the supported speed is literally stated there. Usb-c Gen 1, for example, supports transfer speeds of up to 5 Gbps, with Gen 2 that is already 10 Gbps. Is Thunderbolt 3 also listed? Then that speed increases further to 40 Gbps. The latter is a great advantage when controlling external screens with a higher – for example 4K – resolution. You can also connect an external 4K screen via USB-C, but no more than one. With Thunderbolt 3 you can usually connect multiple screens, and even higher resolutions are supported. Thunderbolt 3 also supports ‘native’ HDMI.
Cable types
Since Thunderbolt 3 supports significantly higher data rates, a different type of cable is also required. So you cannot achieve Thunderbolt speed with a standard USB-C cable. So pay close attention when purchasing. On the other hand, it makes no sense to invest extra in a Thunderbolt cable if you only want to connect a USB 3.x device via USB-C. Furthermore, the cable length for the cheaper passive Thunderbolt 3 cables determines the achievable speed. If you want to reach 40 Gbps, a cable length of up to 0.5 meters is usable. You are more flexible with more expensive active cables (think of a few tens).
USB speeds
As mentioned, USB 3 now exists in various versions. The most recent at the time of writing is USB 3.2, also known as SuperSpeed + (USB 3.1 with a maximum throughput of 20 Gbps is called SuperSpeed). Superspeed + or usb 3.2 has a maximum throughput speed of 20 Gbps (on average somewhere between 1 and 2.4 Gigabyte per second). Even newer is – to complete the confusion – USB 4. This is the first USB standard that is only implemented via the USB-C connection (the 3.x standards are also available via the well-known rectangular USB connections, which are then marked in blue). In fact, usb 4 is usb with integrated Thunderbolt 3, which is why the maximum throughput speed of 40 Gbps sounds awfully familiar. Indeed: it is very careful nowadays with what your ‘simple’ USB-C connector can do exactly!
load
You can (usually) also charge your device via USB-C. The same is also possible with a Thunderbolt 3-capable USB-C connection, only with a higher power. Now there is – how could it be otherwise – a practical problem with charging cables. Many manufacturers optimize their cable either for charging speed or for throughput speed. Both are possible, but that costs an extra pair of wires in the cable. And that does not happen with most fast charging cables. In fact, such USB-C cables often only support USB 2.0 speeds (or a maximum of 480 Mbps).
If you want a cable that can charge (fast) and support USB 3 speeds, read the fine print on the packaging carefully. It often states in very large letters that super-fast charging (of course depending on the power of the charger …) is possible and nice PR terms are used. At the same time, the transfer speed of only 480 Mbps is mentioned somewhere in small print on the back. Such cables cause, for example, the traffic of external hard drives. Only if there is really 5 Gbps or – better still – 10 Gbps throughput speed stated on the intended charging cable, you can use it universally.
But you guessed it: such cables are slightly more expensive and more difficult to obtain. Because a manufacturer prefers to sell both a charging cable and a data cable.
What now?
In practice, as an end user, you have relatively little choice about what possibilities the USB-C port can do on an intended device, the manufacturer has determined that for you. Thunderbolt 3 or USB 4 is only a must if you really want to get the most out of speed and possibilities (for example because you are a pro who definitely wants to use external video cards and / or multiple 4K monitors). Thunderbolt 3 (and increasingly USB 4) can be found on all recent Macs and the better recent laptops. An attention point before you buy if you really need that speed.
For the rest: preferably choose a computer, smartphone, tablet Chromebook, etc. with at least one USB-C connection. Whether or not it supports Thunderbolt 3 or USB 4 is not (yet) very interesting for the vast majority of users. However, you should be careful if you decide to purchase a somewhat older or cheaper laptop (clearance!), For example. Then check whether USB-C is present on it. And if so, whether it supports at least 10 Gbps.
This means that you can also use faster peripherals (think of a fast external SSD) at speed. Although at the same time, 5 Gbps for an external mechanical hard disk is in principle also fast enough. Simply realize that there is a whole hidden world of possibilities behind USB-C, it is certainly not only the connector that – although image-determining – is all-telling.
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