The USB Promoter Group has announced the upcoming release of the USB4 specification. The new standard is based on Intel’s Thunderbolt protocol and supports a range of features, including data transfer rates of up to 40 Gbps, display interfaces, and power delivery. The detailed USB4 specification will be published in the middle of 2019.

The USB4 specification will be based on the Thunderbolt protocol that Intel has contributed to the USB Promoter Group. The new interface will use USB Type-C connectors and will maintain backwards compatibility with USB 2.0, USB 3.2, and Thunderbolt 3 interfaces.  The maximum data transfer rate supported by the new USB4 interface is 40 Gbps over 40 Gbps-certified cables. Also, USB4 will support various display protocols, and power delivery.

The USB4 standard will be officially ratified in the middle of 2019. At present over 50 companies are actively participating in the final stages of development of the draft USB4 specification.


Based on what we know about the USB4 specification at this point, the new standard will use the Thunderbolt protocol, but it will not be exactly Thunderbolt 3 as its functionality will likely be different.

USB Specifications
  USB 1.0 USB 2.0 USB 3.2 Gen 1 USB 3.2
Gen 2
USB 3.2
Gen 2x2
Alternative Branding - High Speed Super
Bandwidth 12 Mbps 480 Mbps 5 Gbps 10 Gbps 20 Gbps 40 Gbps
Encoding 8b/10b 128b/132b
Introduction 1996 2001 2009
(USB 3.0)
(USB 3.1 Gen 2)
2017 2019

The contribution of the Thunderbolt 3 protocol to the USB Promoter Group essentially brings TB3 to mainstream PC platforms and enables various companies to integrate its support into their products. Meanwhile, Intel’s Ice Lake processors will be the first CPUs to support Thunderbolt 3 natively.

“Releasing the Thunderbolt protocol specification is a significant milestone for making today’s simplest and most versatile port available to everyone,” said Jason Ziller, General Manager, Client Connectivity Division at Intel. “By collaborating with the USB Promoter Group, we’re opening the doors for innovation across a wide range of devices and increasing compatibility to deliver better experiences to consumers.”

Related Reading

Sources: USB Promoter Group, Intel

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  • samal90 - Tuesday, March 5, 2019 - link

    can someone answer this to me please?
    At these speeds, could USB4 replace display port and HDMI? We could finally have 1 cable to rule them all.
  • Rudde - Wednesday, March 6, 2019 - link

    Hdmi has a usb-c alternative mode. It's currently capped at v.1.4b (10.2Gbit/s /8.16Gbit/s). It uses all the pins available in usb-c, reconfiguring some of them. It is unclear if hdmi will add support for higher speed usb-c.

    Usb-c includes a displayport alternative mode. Tb has native Display Port support. Although tb3 initially only supported dp1.2, new tb3 controllers support the latest dp1.4 standard. Usb 4 will inherit dp1.4 support.

    You specifically asked about speed. Thunderbolt 3 (and usb4) supports 40Gbit/s data. That is enough for hdmi 2.0b, but not for hdmi 2.1. Hdmi 2.1 needs 48Gbit/s. The next displayport standard is implied to feature speeds up to 65Gbit/s.

    Could usb4 replace dp and hdmi? Yes and no. Usb4 will have support for the latest displayport, but not hdmi. Hdmi 2.0b support could theoretically be added. A future tb4 (or usb4.1) using pcie 4.0 could theoretically double it's speed to 80Gbit/s, enough to replace both the current hdmi and the next dp. At those speeds I could envision a 1 cable to rule them all.
  • Rudde - Wednesday, March 6, 2019 - link

    Edit: Newest ThunderBolt controllers support hdmi 2.0. I can assume usb 4 also will.
  • ABR - Tuesday, March 5, 2019 - link

    12M, 480M (x40) 5G (x10) 10G, 20G, 40G (collectively x8). "Peak USB" is coming..
  • Deb.roy - Tuesday, March 5, 2019 - link

    Nice opinion. You can Readout mine in details
  • Deb.roy - Tuesday, March 5, 2019 - link

    Nice opinion. You can Readout mine in details

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