Thunderbolt and USB4 cables are USB-C cables built for 40 Gbps data transfer, external displays and laptop charging over a single connection. They suit anyone linking a laptop or desktop to a dock, a fast external SSD or a high-resolution monitor.
Cable type, length and certification decide whether you get the full speed, so those details matter more than the connector shape.
How to choose a Thunderbolt or USB4 cable
Standard. Thunderbolt 4 cables guarantee 40 Gbps, support for two 4K displays or one 8K display, and charging up to 100 W. Thunderbolt 3 cables also reach 40 Gbps but carry fewer guarantees. USB4 cables run at either 20 Gbps or 40 Gbps, so check which one is printed on the product.
Length. Passive cables keep 40 Gbps only over short runs, and the shortest ones, around 0.8 m, are the safest for the highest speeds. Thunderbolt 4 passive cables can reach 2 m at full speed. For anything longer, choose an active or optical cable.
Charging power. Many of these cables carry up to 100 W, which covers most laptops. Some are rated for 240 W under the newer USB Power Delivery standard. Match the rating to your laptop charger, since a cable rated lower than the charger will limit charging.
Display needs. If you plan to drive a 4K monitor at a high refresh rate or two monitors from one port, pick a certified 40 Gbps cable. A basic USB-C charging cable will not carry video or fast data reliably.
Device compatibility. The cable only works as fast as the slowest part of the chain. Check that the laptop port, the dock or drive and the cable all support Thunderbolt or USB4 before you buy.
Cable types to look at
- Thunderbolt 4 cables: certified for 40 Gbps with a full set of display and charging features, which makes them the simplest choice for docks and multi-monitor desks.
- Thunderbolt 3 cables: work with many older laptops and docks, and are still suitable for fast external storage.
- USB4 cables: follow the open USB standard and are backward compatible with USB 3 and USB 2 devices, though speeds vary between 20 Gbps and 40 Gbps.
- Active and optical cables: use signal boosting or fibre to keep 40 Gbps over lengths beyond what passive copper manages.
Look for the Thunderbolt or USB certification logo and the printed speed rating rather than relying on a manufacturer name alone.
Frequently asked questions
Is a Thunderbolt cable the same as a USB-C cable?
No. Both use the same oval USB-C connector, but a Thunderbolt cable is built and certified for 40 Gbps data, video and higher power. Many ordinary USB-C cables only support charging or slow data speeds.
Can I use a USB4 cable with a Thunderbolt port?
Yes, in most cases. Thunderbolt 3 and 4 ports accept USB4 cables, but the speed depends on the cable. A 20 Gbps USB4 cable will not give you the 40 Gbps a Thunderbolt device can offer.
How long can a Thunderbolt 4 cable be?
A passive Thunderbolt 4 cable can be up to 2 m and still run at 40 Gbps. Longer lengths need an active or optical cable, which keeps the signal strong over greater distances.
Will a Thunderbolt cable charge my laptop?
Yes, if the cable and the laptop both support USB Power Delivery at the required wattage. Many Thunderbolt cables carry up to 100 W, which suits most laptops. Check your charger's rating and choose a cable that matches or exceeds it.
