- Connecting
- Need
- Answer
Cable for a Thunderbolt or USB4 SSD or dock
Get this
Thunderbolt 4 / USB4 40Gbps cable (Thunderbolt 5 for 80 Gbps)
Look for
- Thunderbolt or USB4 40Gbps on the cable
- Passive cables 0.8 m or shorter; longer must be active Thunderbolt 4
Avoid
- Thunderbolt 3 cables over 0.5 m without a "40": 20 Gbps only
Speed in practice
| Link | Signalling | Typical real copy speed |
|---|---|---|
| USB 2.0 | 0.48 Gbps | 35–40 MB/s |
| USB 5Gbps | 5 Gbps | 400–450 MB/s |
| USB 10Gbps | 10 Gbps | 900–1,050 MB/s |
| USB 20Gbps | 20 Gbps | 1,800–2,000 MB/s |
| USB4 / Thunderbolt 40Gbps | 40 Gbps | 2,800–3,800 MB/s |
Typical figures for good drives, as commonly measured; slower drives won't reach them.
Standards behind this answer
2020
Thunderbolt 4
The same 40 Gbps as Thunderbolt 3, with the minimums raised so every port behaves the same.
- data: 40 Gbps (PCIe 32 Gbps)
- video: two 4K 60 Hz or one 8K
- power: up to 100 W (USB PD)
USB4 (20 and 40 Gbps)
Thunderbolt 3's protocol, opened up as a USB standard. Tunnels USB, DisplayPort and PCIe over one cable.
- data: 20 or 40 Gbps
- video: DisplayPort tunnelled
- power: USB PD required
Thunderbolt 5
80 Gbps both ways, 120 Gbps towards displays. Intel's certified USB4 Version 2.0.
- data: 80 Gbps (120 boost)
- video: multiple 4K 144 Hz / 8K
- power: up to 240 W