About the transmission protocols supported by Thunderbolt 4 interface

[CQCQN]

When TB4 transmitting PCIe data, does Thunderbolt 4 support negotiation into a PCIe 4.0 channel for transmission? Although limited by the total 40 Gbps speed, but is there a controller that can do this? Or just support 4 PCIe 3.0 channels to realize data transmission function.

Thanks for replay.

[DhannielM_Intel · Accepted solution]

Hello CQCQN, 

Thank you for your post in the community. Let me clarify the details regarding Thunderbolt 4 and its support for PCIe channels.

While Thunderbolt 4 maintains the same 40 Gbps bandwidth as Thunderbolt 3, it does not inherently support PCIe 4.0 channels. Instead, Thunderbolt 4 supports up to four PCIe 3.0 lanes for data transmission. As you seem to be aware, there is currently no Thunderbolt 4 controller that supports PCIe 4.0 for data transmission. This limitation is due to the bandwidth constraints and the design of the Thunderbolt 4 standard.

However, the implementation can vary depending on how system manufacturers develop their technologies. To assist you further, could you please specify whether you are using a laptop or a desktop? If it's a laptop, please provide the full make and model. For a desktop, the exact model of your motherboard would be helpful.

For more information you can check on this link as well: 

Support Options for Thunderbolt™

What’s the Difference Between Thunderbolt™ 4 and USB-C?

Best regards,

Dhanniel M.

Intel Customer Support Technician

[CQCQN]

Thx for reply.

I saw on the Internet that an unreleased product uses Thunderbolt 4 for connection. In that video, HW_info software shows that the negotiated bandwidth is pcie4.0 x4. This is different from my usual understanding(TB4 in pcie mode use pcie3.0 x4 factor to trans data), so I asked this question. I just want to know whether tb4 has design specifications in this regard. And I have not encountered any related hardware problems that need to be solved.

You have answered my question perfectly and you can close this question.

[DhannielM_Intel]

Hello CQCQN, 

I'm pleased to hear that I was able to address your inquiry. Since you've indicated that I can close this inquiry, I will proceed to do so. If you require further assistance, please submit a new question, as this thread will no longer be monitored.

Best regards,

Dhanniel M.

Intel Customer Support Technician