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During its CES 2020 press conference, Intel surprisingly announced that Thunderbolt 4 will be built into its next Core-i generation Tiger Lake. The company mentioned this in a side-note without providing any further details. The announcement is odd. Because Intel actually stopped developing Thunderbolt in 2019 and donated the standard to the USB Promoter Group USB-IF, which used Thunderbolt as the basis for developing USB 4.

Later during the CES, Intel made several clarifying statements towards the press. In a nutshell, the difference between USB 4 and Thunderbolt 4 is that USB contains several features that are optional and don’t have to be implemented by manufacturers. This includes features like tunneled PCIe connections. Furthermore, USB 4 allows for slower link speeds with just 20 Gbit/s. Support for 40 Gbit/s can essentially be turned off to save cost.

Thunderbolt 4, on the other hand, makes all USB 4 features mandatory and always supports the highest link speed of 40 Gbit/s (while being compatible with slower USB 4 connections). Meaning, Thunderbolt 4 is actually USB 4 maxed out.

In other words: If you want the full USB 4 feature set with the highest possible link speeds, choose Thunderbolt 4. Or make sure that whatever device or mainboard you are buying has all the USB 4 features enabled that you want. Things like DisplayPort to connect to monitors or PCIe passthrough to connect to eGPUs come to mind here.

Thunderbolt 4 is USB 4 and USB 4 is Thunderbolt 3

Thunderbolt 4 itself did not receive any significant updates. It’s basically just a rebranded Thunderbolt 3 with the addition of supporting USB 3.2 link speeds. So in conclusion, USB 4 is basically Thunderbolt 3 with the option of leaving out some of its features. Confusing, right?

USB is more complicated than it should be

USB has always been more complicated than it should be, with all its different standards, speeds, connectors, and brand names. And it looks like the USB-IF is not going to change much about that with USB 4 either. It remains a mess.

Still, to make it a bit easier for consumers to understand, the USB-IF has come up with new logos that offer some guidance when it comes to the different link speeds that USB 4 supports. These logos, however, don’t tell you whether features like PCIe tunneling are available or not.

USB 4 Logo
USB 4 Logos

USB 4 and Thunderbolt 4 availability; Connectors

With Tiger Lake set to release this summer, it’s very likely that we will see devices supporting these standards before the end of the year. The physical connector will remain USB-C for both standards.

Save your money and skip USB 3.2

Before the USB 4 and TB 4 announcements, USB 3.2 was meant to be the next big step for USB, with the major new feature being a link speed of 20 Gbit/s. However, now that USB 4 and TB 4 devices are just around the corner, USB 3.2 will probably be a very short-lived standard that won’t see much traction. If manufacturers want to support higher speeds than USB 3.1 delivers today (10 Gbit/s), USB 4 or TB 4 are much better choices than USB 3.2.

It’s not unlikely that mainboard manufacturers will bring out some USB 3.2 boards this year, but your best bet is to wait for USB 4 / TB 4. USB 3.2 will just be a transitional solution with limited availability. The only USB 3.2 controller that exists to date is the ASMedia ASM3242, and it’s very likely that it will remain the only one.

Opinion and bottom line

Thunderbolt 4 and USB 4 are essentially the same thing. With some caveats. If you ask me, the USB-IF should have just taken Thunderbolt and make it the defacto USB 4 standard – without making it possible to skip on features and higher link speeds. It would have made things a lot easier for consumers and device compatibility. And it would have ended the sheer chaos surrounding the bazillion different USB flavors. Plus, everybody would get the best features available.

Bottom line is, if you’re in the market for a new rig or upgraded peripherals, wait just a little longer and go with Thunderbolt 4 on your next mainboard. That will be the only no-compromise solution. Given that Thunderbolt is now royalty-free, manufacturers can offer Thunderbolt without incurring licensing costs, so it’s likely that Thunderbolt will see a lot more traction in the market going forward. If you go with USB 4 instead, double-check that all your required features are actually supported.

What do you think? Let me know in the comments section below.



  • TB4 is not even finalized the performance and Intel didn’t even confirmed anything except 4 times faster than USB 3. PCWorld asked Intel from CES 2020 for clarification but Intel told them to wait for more info in future.

    And seriously, what’s the point of keeping 40 Gbps when TB3 also has 40 Gbps?

    • Intel clearly stated in their press release that TB4 will have “4x the throughput of USB 3”, which puts it at 40 Gbit. You can find the press release here: https://newsroom.intel.com/news-releases/intel-ces-2020/#gs.raxbpe

      Intel also announced last year that they will not continue development of Thunderbolt because they have “open sourced” the standard and donated it to the USB-IF. We linked the press release to that in the article. This means, TB4 will not get any speed improvements over TB3.

  • It’s really worth noting that Intel has successfully pulled the wool over most people’s eyes regarding Thunderbolt being “royalty-free.” The article is otherwise well written, with the exception of this comment. As a device maker, you can potentially make something that is thunderbolt compatible without paying Intel an additional license fee, but you actually cannot sell that and product as a thunderbolt compatible product until you pay Intel and related test labs for thunderbolt certification. The USB4 specification has a chapter that describes how to make thunderbolt compatible devices, but that alone is not sufficient because thunderbolt is also a trademark and usage of that trademark subjects you to specific rules.

  • It’s really worth noting that Intel has successfully pulled the wool over most people’s eyes regarding Thunderbolt being “royalty-free.” The article is otherwise well written, with the exception of this comment. As a device maker, you can potentially make something that is thunderbolt compatible without paying Intel an additional license fee, but you actually cannot sell that and product as a thunderbolt compatible product until you pay Intel and related test labs for thunderbolt certification. The USB4 specification has a chapter that describes how to make thunderbolt compatible devices, but that alone is not sufficient because thunderbolt is also a trademark and usage of that trademark subjects you to specific rules.

    • Thanks for the pointer there. I’ll do some more research on it.

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