Intel demonstrated a Tiger Lake system on stage in their CES 2020 keynote yesterday. One of the interesting aspects was the teaser of Thunderbolt 4, with a mention of it offering four times the speed of USB 3. After reaching out to Intel for additional details, it appears that they are not ready yet to share more information.

Intel did confirm that that they were referencing USB 3.2 Gen 2 - the 10 Gbps version - in the keynote presentation. This means that the peak speeds (40 Gbps) are not changing relative to Thunderbolt 3. Given that the Thunderbolt 3 specifications have been donated to USB-IF for USB 4.0, it appears likely that Thunderbolt 4 may be a push for Intel certification of certain Type-C ports. We look forward to receiving more concrete information from Intel regarding the new features, if any, in Thunderbolt 4.

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  • jeremyshaw - Tuesday, January 7, 2020 - link

    TB3 is currently around 22Gbps data, with the rest wasted on a DP allocation that cannot be repurposed, even when there is no video stream whatsoever.

    Does TB4 change this relationship?
    Reply
  • ltcommanderdata - Tuesday, January 7, 2020 - link

    I believe existing TB3 controllers also have a problem with uneven performance when the 2nd TB3 port in a controller is used to connect regular USB devices. The 22 Gbps limit, the USB connection stability issue, USB 3.2 2x2 compatibility, there are definitely useful improvements that TB4 can hopefully address even if the theoretical bandwidth isn't increasing.

    I guess we'll probably have to wait for Intel PCH to adopt PCIe 4.0 before Thunderbolt gets more raw bandwidth, which could take a while seeing their CPU's don't even support PCIe 4.0 yet.
    Reply
  • Santoval - Tuesday, January 7, 2020 - link

    PCIe 4.0 has much stricter signaling requirements, so a hypothetical 80 Gbps Thunderbolt based on PCIe 4.0 would require super expensive cables. Their maximum length would also need to be shorter, so it might make more sense to use a fiber optics cable rather than copper. The problem with fiber is that it cannot provide power though. Reply
  • TheUnhandledException - Tuesday, January 7, 2020 - link

    Nothing prevents you from having a hybrid cable (optical for data and copper for power). Even on TB3 power is carried by seperate wires. The big issue with optical is cost. Assumming you are using standard usb-c connector it means an electrical to optional converter in the cable at both ends. That is going to mean really expensive cables. However to go to 80+ Gbps you might not have much choice. Reply
  • brakdoo - Tuesday, January 7, 2020 - link

    I don't think he meant active cables. The optical transceiver should be in your laptop and the end device (like monitor). Reply
  • jeremyshaw - Tuesday, January 7, 2020 - link

    Active cables during TB2 ended up being a sore point for the suppliers, AFAIK. The photonics were only provided by Intel, and had a high enough failure rate that nobody went on to develop TB3 optical cables.

    I somewhat wonder who supplied the original joint venture (Light Peak) with Sony. Did Sony have photonics back then? Did Intel?
    Reply
  • repoman27 - Tuesday, January 7, 2020 - link

    Light Peak / Thunderbolt never used silicon photonics. The optical versions were based on conventional 850nm VCSELs from Oclaro, PIN photodiode receivers from Enablence, embedded optical engine from Avago, optical module by SAE, driver and receiver silicon from IPtronics, transceiver IC from Ensphere, and multi-mode fiber and waveguides from FOCI.

    Thunderbolt optical cables were developed using more or less off-the-shelf optical transceivers and fiber because they only needed to support 10.3125 GT/s NRZ signaling, which is rather common. Thunderbolt 3 would require transceivers capable of at least 20.625 and 10.3125 GT/s modes that also fit within the footprint and power budget of a Type-C cable connector. I'd be very surprised if anyone bothered to develop optical transceivers specifically for Thunderbolt 3 applications because the addressable market is tiny (1000's of units).
    Reply
  • TheUnhandledException - Tuesday, January 7, 2020 - link

    There is zero chance of that happening. One reason TB3 is at least marginally adopted is it is a usb-c port. So it is usb AND TB3. You can plug a TB3 device in or a usb device in. A special optical port only used by Thunderbolt isn't happening. Hell it is hard enough to get OEMs to keep widely used ports like HDMI and ethernet on laptops they aren't putting a special TB only optical port. Reply
  • rahvin - Tuesday, January 7, 2020 - link

    As much as I like TB, it's a dead standard. Even if Intel increments it it's going nowhere.

    If the USB forum wasn't so brain dead with their naming conventions and inability to force the manufacturers to a clear naming scheme TB would have died quicker than it did. Honestly anything with a licensing fee as big as Intel wanted for TB is a dead standard when USB3 is good enough. TB never saw anything other than niche use, and with it's guts contributed to USB-IF it might see broad adoption in 10 years after USB fully integrates it in the next version but otherwise it's not going anywhere. It just can't compete against USB when USB chips can be had for pennies.

    Intel's foolish if they keep spending money developing TB hoping it will go somewhere.
    Reply
  • repoman27 - Tuesday, January 7, 2020 - link

    Apple alone buys ~$150M / yr. in Thunderbolt controllers, which is probably more than Intel makes off of client Wi-Fi solutions, so there's that. If you can make decent money serving the niche applications that USB can't, why wouldn't you? Reply

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