Thunderbolt 4, Thunderbolt 5 and USB4 Cables
Thunderbolt 4 runs at 40 Gbps, Thunderbolt 5 at 80 Gbps with a 120 Gbps display boost, and USB4 comes in 20, 40 and 80 Gbps, all on the USB-C plug.
By Liam McCabeContributing writer.
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The short answer
Thunderbolt 4, Thunderbolt 5 and USB4 all use the USB-C plug, so the cables look alike. The difference is how much data, video and power they are built to carry:
- Thunderbolt 4: 40 Gbps.
- Thunderbolt 5: 80 Gbps in each direction, and up to 120 Gbps toward a display when needed.
- USB4: some cables and devices run at 20 Gbps, some at 40 Gbps and some at 80 Gbps, so the label matters.
How Thunderbolt and USB4 are related
USB4 is the USB standard, and the USB Implementers Forum says it is based on the Thunderbolt protocol that Intel contributed. Thunderbolt is Intel's certified version on top of it: Intel's Thunderbolt 5 brief lists USB4 compliance as a requirement for both Thunderbolt 4 and Thunderbolt 5, and says Thunderbolt 5 builds on USB4 version 2 and DisplayPort 2.1. Intel adds rules USB4 leaves open, such as minimum speeds and charging, and certifies every Thunderbolt computer, accessory and cable.
USB4 works with older USB 3.2, USB 2.0 and Thunderbolt 3 gear, and a connection runs at the highest speed both ends support.
Thunderbolt 4 vs Thunderbolt 5
Intel publishes these figures for computers with each port:
| Feature | Thunderbolt 4 | Thunderbolt 5 |
|---|---|---|
| Speed | 40 Gbps | 80 Gbps, 120 Gbps with Bandwidth Boost |
| Video | Two 4K displays | Two 6K displays |
| PCIe data (storage, external graphics) | 32 Gbps | 64 Gbps |
| Laptop charging on at least one port | Required up to 100W, available up to 140W | Required up to 140W, available up to 240W |
| Power for accessories | 15W | 15W |
| Passive cable up to 2 meters | 40 Gbps | 120 Gbps |
Bandwidth Boost is for screens. Normally a Thunderbolt 5 link carries 80 Gbps each way. When monitors need more, it shifts to 120 Gbps going out and 40 Gbps coming back.
USB4 speeds and labels
USB-IF says USB4 can reach 80 Gbps over cables certified for 80 Gbps. Cable Matters notes that the first USB4 version tops out at 40 Gbps, that version 2 adds 80 Gbps, and that a cable must be labeled 80Gbps to reach it. A USB4 cable with no speed on the box or the listing may be a 20 or 40 Gbps cable.
Which cable to buy
- Thunderbolt 5 laptop and dock or fast external drive: a certified Thunderbolt 5 cable, so the link to a Thunderbolt 5 dock is not held back by the cable.
- Thunderbolt 4 or USB4 40 Gbps gear: a Thunderbolt 4 or 40 Gbps USB4 cable is enough, including for Thunderbolt 4 docks.
- Laptop charging through the cable: check the cable's watt rating against your charger, since a Thunderbolt 5 port can be built to deliver up to 240W.
- Length: Intel's speed figures above are for cables up to 2 meters (about 6.6 feet). On Wiki Shopping, the most common lengths are 3.3 feet with 12 cables, 6.6 feet with 11 and 10 feet with 10. For longer cables, read the listed speed.
Of the 57 Thunderbolt cables on Wiki Shopping, 48 cost under $50 and 40 cost under $25.
How we count
The counts come from the 57 Thunderbolt cables listed on Wiki Shopping on October 26, 2026. Length and price are read from each store listing; cables that do not state a length are left out of the length counts. The counts change as listings are added or removed.