With the arrival of Thunderbolt 4, choosing the right cable for USB-C and Thunderbolt computers and devices has become a lot easier.
The short answer, which I’ll explain here, is that if you’re looking for absolutely the best cable to buy for USB-C, Thunderbolt 3 or Thunderbolt 4, you should aim for an Intel-certified Thunderbolt 4 cable.
If someone needs to buy a Thunderbolt 3 cable right now they might as well buy a universal Thunderbolt 4 cable since it is backwards compatible with everything, and they have the benefit of future-proofing their cable.
Thunderbolt 4 is simpler and more powerful
Previously, there were USB-C cables and Thunderbolt 3 cables, and each could be “active” or “passive”.
A passive USB cable merely carries data that's transferred through it.
An active USB cable includes small electronic circuits that boost the intensity of the data carried by the cable, which can stop signal degradation due to the length of the cable. There are active Thunderbolt 3 cables that can hit 40Gbps bandwidth at 2m. But you can expect to pay a lot more for active cables than shorter passive ones - around double the price of passive cables.
Note that USB-C is just the connector. The data-transfer speed or bandwidth is determined by the version of USB it uses. USB speeds range from slow USB 2.0 (480Mbps) to fast USB 3.2 Gen 2x2 (20Gbps), with Thunderbolt 3 and 4 reaching 40Gbps.
And the length of the cable matters, too.
USB-IF, the official USB Implementers Forum, dictates that passive USB 3.2 Gen 1 (5 Gbps) cables should be at most 2 metres, while USB 3.2 Gen 2 (10 Gbps) cables can reach only up to 1 metre if it is to keep transferring data at its maximum speed.
An active USB-C 3.2 Gen 2 cable can be up to 3m in length.
The maximum length of a passive Thunderbolt 3 cable is just 0.8m at full 40Gbps bandwidth, or 2m at 20Gbps bandwidth.
What is Thunderbolt 4?
Thunderbolt 4 is the latest version of Intel's Thunderbolt line. It is backwards compatible with Thunderbolt 3 and USB-C, and has a range of benefits.
All certified Thunderbolt 4 cables work with everything, including USB4, USB 3.2, USB 3.1, and even USB 2.0 - no matter their length.
Thunderbolt 4 allows for up to 40Gbps data transfer, 100W power delivery (PD) and laptop charging. This was true of Thunderbolt 3, but some Windows PC sand laptops used cut-down versions. To be officially certified as Thunderbolt 4 by Intel, all manufacturers have to supply the top specifications T4 offers.
T4 can also support high-resolution displays up to 8K (7,680-x-4,320) or any USB-C monitor. Buying a USB-C display means you can use a Thunderbolt 4 cable that’s much thinner than a DisplayPort or HDMI cable. It can also be used with many devices other than displays, unlike video cables.
Previously, 2m cables could not be used with USB-C monitors - a limitation rectified by Thunderbolt 4.
Thunderbolt 4 benefits
- Support for two 4K displays or one 8K display
- 40Gbps bandwidth
- PCIe at 32Gbps for data-storage speeds up to 3,000MBps
- Support for docks with up to four Thunderbolt 4 ports
- Up to 100W PD charging on at least one computer port
- Wake the computer from sleep by touching the keyboard or mouse when connected to a Thunderbolt dock
- Intel VT-d direct memory access (DMA) protection to prevent physical DMA attacks
With Thunderbolt 3, only passive cables were backwards compatible (and then only at a feeble 480Mbps), meaning longer active T3 cables worked with T3 devices only.
In comparison, 2m Thunderbolt 4 cables support all versions of USB, so buying Thunderbolt 4 will future-proof your cable purchase as well as offer backwards-compatibility.
With a T4 cable, you gain the versatility to connect USB-C devices to Thunderbolt ports.
In addition, since Thunderbolt 4 supports USB4, if someone needs a USB4 cable they can use a Thunderbolt 4 cable.
One of the benefits of Thunderbolt 4 cables for USB4 users is that Thunderbolt 4 cables always support up to 40Gbps - USB4 is rated at either 20Gbps or 40Gbps, so T4 is ready for both.
You can attach a powerful wall charger up to 100W, but note that Thunderbolt and USB-C charging functionality is dependent on your host computer’s charging capabilities. Some Windows PC manufacturers limit charging on their ports. Either way, a T4 cable is capable of the maximum.
With Thunderbolt 4 there is no difference between passive and active, and Intel-certified 0.8m and 2.0m cables should act exactly the same.
Cables are currently available in lengths of either 0.8m (2.6ft) or 2m (6.6ft).
There are certainly more options on length and looks with other recommended USB-C and Thunderbolt 3 cables, but Thunderbolt 4 cables win on features and backwards/future compatibility.
Like Thunderbolt 3, Thunderbolt 4 ports and cables show the small lightning bolt logo, which helps to differentiate T4 from USB4 and older USB-C 3.2 ports. Thunderbolt 4 cables include a small number 4 underneath the lightning bolt logo.
What is USB4?
USB4 takes over from the often confusing USB 3.0 to 3.2, offering either 20Gbps or 40Gbps data speeds. It uses the same rounded, reversible Type-C connector as USB-C, Thunderbolt 3 and 4.
A Thunderbolt 4 cable is also a USB4 cable, but not all USB4 cables will be certified for use with Thunderbolt 4 or even Thunderbolt 3 - which is another reason that a T4 cable is our universal recommendation.
USB4 is more efficient at sharing between data and display protocols as it can dynamically monitor bandwidth requirements for connected displays and save the remaining bandwidth for data transfer. Older USB simply split the bandwidth in two for display and data.
USB4 can support Power Delivery up to 100W.
And, like Thunderbolt 4, USB4 is backwards compatible with USB 3.2, USB 3.1, USB 3.0, USB 2.0, and Thunderbolt 3.
A certified USB4 cable will feature the USB logo plus either the number 20 or 40 depending on the speed (20Gbps or 40Gbps) it is rated at.
More details are available on Thunderbolt 4 vs Thunderbolt 3 vs USB4.
Thunderbolt 4 devices on the way
While a Thunderbolt 4 cable will work with older Thunderbolt 3 and USB-C devices, new Thunderbolt 4 docking stations and hubs are being launched to take advantage of the ability to include multiple T4 ports.
Meanwhile, here are the best Thunderbolt 4 cables available today.
CalDigit Thunderbolt 4 / USB4 Cable (0.8m)
Caldigit's shortest and most affordable Thunderbolt 4 / USB4 cable measures 0.8m, which is about 2.6 feet.
It is Intel certified, and of a quality you can expect from one of the leading Thunderbolt dock, hub and accessory manufacturers, built with premium materials to maintain consistent performance and reduce heat.
It includes E-Marker chips at either end of the cable, which communicate with attached devices to provide the correct amount of power in order to prevent damage to your devices caused by an excess of power.
It is backwards compatible with Thunderbolt 3, USB4, USB 3.2, USB 3.0 and USB 2.0, and comes with a two-year warranty.
CalDigit Thunderbolt 4 / USB4 Cable (2m)
If you need a longer Thunderbolt 4 or USB4 cable, look for a 2m length.
Thanks to the magic of Thunderbolt 4, such a long cable doesn't need to be "active" to keep its full data load at this length.
Like its 0.8m T4/USB4 cable, the 2m cable is backwards compatible, features E-Marker technology and has a two-year warranty.
Cable Matters USB4 Thunderbolt 4 Cable (0.8m)
Cable Matters, as its name suggests, is something of a specialist in cables, and it offers a 0.8m Thunderbolt 4 / USB4 cable that is Intel certified, backwards compatible, and capable of all the advantages of the new T4 standard.
Its T4/USB4 cables feature active repeater chips that boost the signal, preserving full 40Gbps performance.
Cable Matters USB4 Thunderbolt 4 Cable (2m)
0.8m length is probably fine to connect your laptop or PC to a nearby docking station, but it might be too short to connect to that second or third display.
Cable Matters sells an Intel-certified 2m Thunderbolt 4 cable that is also compatible with USB4.
2m should be enough if you need to link to a device, such as a monitor, that is some distance from your laptop or docking station.
Cable Matters USB4 Cable (0.8m)
While Thunderbolt 4 cables are compatible with USB4, not all USB4 cables work with Thunderbolt 4.
This premium cable is certified to work with USB4 at full 40Gbps bandwidth.
OWC Thunderbolt 4 / USB-C Cable (0.8m)
OWC makes quality accessories, targeted especially at users of Apple products.
Its Thunderbolt 4 and USB4 cable is universal and certified by Intel, but available only at a length of 0.8 metres.
It has a three-year guarantee, and is compatible with USB-C, Thunderbolt 3 and, of course, Thunderbolt 4.