The first USB 3.2 Gen 2×2 devices are expected to ship this year, offering data transfer speeds up to 20 Gbps. But less than a week after announcing the impending arrival of the new technology (and a confusing re-naming of previous-gen USB standards), the USB Promoter Group has announced that USB4 is on the way… and it’ll offer up to twice the speed.

That’s because Intel has contributed its Thunderbolt 3 protocol specifications to the USB Promoter Group, which basically means that all USB4 ports and cables should support speeds up to 40 Gbps.

That’s the theoretical max speed that’s already offered by devices with Thunderbolt 3 ports. But there are only around 450 certified Thunderbolt 3 devices at the moment.

Since Intel is offering up the specification royalty-free, it will now be easier (and cheaper) for device makers offer 40 Gbps speeds by adopting USB4.

USB4 is backward-compatible with USB 3.2, USB 2.0, and Thunderbolt 3. So if you buy a device that uses the new standard (such as a laptop, tablet, smartphone, charger, or cable), you should be able to use it with previous-gen devices. You just may not get slower speeds.

In addition to high-speed data transfer, USB4 should benefit from some other Thunderbolt 3 features including support for driving video displays (replacing the need for separate DisplayPort or HDMI ports and cables) and up to 100 watts of power delivery (potentially replacing the need for separate charging ports and power adapters).

The USB Promoter Group says it’ll share detailed specifications for USB4 later this year. It’s not clear when you’ll be able to actually get your hands on devices that make use of the new standard.

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11 replies on “USB4 will support speeds up to 40 Gbps (incorporates Thunderbolt 3 tech)”

  1. The improvement is less than what the paper specs say.
    USB 3.0 is also 10x faster tan USB 2.0 on paper, but the
    real world speed diffference is only 4x.

    So USB4 will likely only be 4x faster than USB 3.0, unless,
    of course, they also improve everything to squeeze out
    something that reaches more of the spec’s potential.

  2. …nah screw that, I’m going to stick to my own nomenclature for USB (speeds rounded off):
    USB 1.0 = 1.5Mbps
    USB 1.1 = 15Mbps
    USB 2.0 = 500Mbps
    USB 3.0 = 5Gbps
    USB 3.1 = 10Gbps
    USB 3.2 = 20Gbps
    USB 4.0 = 40Gbps

    I wonder how this affects bandwidth, for instance, there’s a big difference between a Common TB3 (PCIe x2-Lane) port and a Full TB3 (PCIe x4-Lane) port. Hopefully, it will stick to the (full) latter and call it a day.
    …and even more curiously, once you stick a new 2019 Ultrabook with “USB 4” into an eGPU enclosure, will the eGPU box work normally, would it recognise it as TB3 port, would it make a connection at all??

  3. My USB3 thumb drives appear to thermal throttle when I transfer lots of files. Is USB4 going to be any different?

    1. Higher speeds usually lead to more heat, thus you get sooner the same

      I’m kind of curious wha kind of chaos the usb committee can come up with. I have no doubt that usb4 will be incompatible with some tb3 devices and many cheap usb4 devices and usb4 cables not working as you expect.

      1. I believe it is the flash memory IC write cycles that are causing the majority of the heat (as opposed to the flash memory pin IO, which is not differential). This makes me think that without a means to dissipate the heat, small USB drives will not benefit from new USB standards.

    2. a thumb drive is more for transfers. A faster speed will mean quicker transfers and less time spent getting hot, but if you’re going to use it form something more long-term like running an OS -then you’ll always be better off with a regular sized drive.

    3. Good interoperability standards are forward looking. They are supposed to anticipate where the technology will be years from now, and not just today.

      Also, thermal throttling is all to do with the capabilities of the memory your thumb drive is using, and has nothing to do with which version of USB connector you’re using.

    4. That’s not going to have anything with the protocol. That’s just poor construction of a USB drive. Probably a low quality IC or memory.

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