USB4 Explained: 40 Gbps, 80 Gbps and Thunderbolt Compatibility
Connectivity · Updated · First published · By the Hardware Spec Index editors
USB4 was published by the USB Implementers Forum in 2019, based on the Thunderbolt 3 protocol. It uses only the USB-C connector and tunnels USB, DisplayPort and PCIe traffic over a shared link.
Key facts
| Published | 2019 (v1.0), 2022 (v2.0) |
|---|---|
| USB4 v1 speeds | 20 or 40 Gbps |
| USB4 v2 speeds | 80 Gbps, or 120/40 Gbps asymmetric |
| Connector | USB-C only |
| Tunneled protocols | USB 3.x, DisplayPort, PCIe |
| Passive 40 Gbps cable | Up to 0.8 m |
| Retail names | USB 40Gbps, USB 80Gbps |
Versions and speeds
USB4 Version 1.0 supports 20 Gbps and 40 Gbps. USB4 Version 2.0, published in 2022, adds 80 Gbps symmetric operation and an asymmetric 120/40 Gbps mode using PAM3 signaling. Retail packaging uses names such as USB 40Gbps and USB 80Gbps.
Tunneling
A USB4 link carries several protocols at once: USB 3.x data, DisplayPort video and, optionally, PCIe. Bandwidth is shared dynamically, so a high-resolution display reduces what is left for storage.
Thunderbolt relationship
Thunderbolt 4 is a certified profile of USB4 at 40 Gbps with mandatory PCIe tunneling, dual 4K display support and Thunderbolt 3 compatibility. Plain USB4 hosts may omit some of these, so check the specifications when buying docks or enclosures.
Top-ranked matching records
Highest normalized benchmark index among Thunderbolt & USB4 Docks, Motherboards, Laptops, PCIe Cards & NVMe Enclosures in our database that match this guide. Rankings are data, not reviews.
| Model | Category | Benchmark | Price |
|---|---|---|---|
| Halcyra LX-1173 Ti 18" Gaming Laptop (8GB GDDR6) | Laptops | 20,694 | $2,609 |
| Orbita LX-8134 SE 16" Gaming Laptop (6GB GDDR6) | Laptops | 16,930 | $1,409 |
| Kestrix LX-4362 Plus 16" Creator Laptop (8GB GDDR6) | Laptops | 15,153 | $1,369 |
| Quorvex LX-5751 XT 16" Gaming Laptop (12GB GDDR7) | Laptops | 12,921 | $999 |
| Quorvex LX-8698 Plus 14" 2-in-1 Laptop | Laptops | 9,988 | $699 |
| Tessarix DK-3016 Edge USB-C 10Gbps Dock (100W) | Thunderbolt & USB4 Docks | 6,085 | $389 |
| Tessarix DK-5305 Core USB-C 10Gbps Dock (100W) | Thunderbolt & USB4 Docks | 6,038 | $369 |
| Tessarix DK-4440 Ti Thunderbolt 4 Dock (96W) | Thunderbolt & USB4 Docks | 5,437 | $309 |
Frequently asked questions
Is USB4 the same as Thunderbolt 4?
Thunderbolt 4 is a stricter, certified implementation of USB4 at 40 Gbps; every Thunderbolt 4 port is USB4, but not every USB4 port meets Thunderbolt 4 requirements.
Do Thunderbolt 3 devices work on USB4?
Often, but Thunderbolt 3 compatibility is optional for USB4 hosts.
How fast is a USB4 NVMe enclosure?
Around 3.8 GB/s in practice at 40 Gbps.
Does every USB-C port support USB4?
No. USB-C is only the connector; many USB-C ports run at 5, 10 or 20 Gbps.
What cable do I need for USB4 40Gbps?
A USB4 40Gbps or Thunderbolt 4 cable; passive cables are limited to about 0.8 m.
Terms in this guide
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Cite this page: Hardware Spec Index, “USB4 Explained: 40 Gbps, 80 Gbps and Thunderbolt Compatibility”, https://vextor7.com/topics/usb4 (accessed 2026-10-19).