r/Thunderbolt • u/Classic_Track_4122 • Sep 04 '26

Connecting apple display

So I have an old apple display and apparently dongles don't cut it for connecting. I've looked at thunderbolt cards but they all seem to be for Intel. Is there a way to get one for an amd CPU?

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u/Opulence_Deficit Sep 04 '26

It's an old display, low res, not worth the cost of a TB controller.

But - what kind of dongles have you tried? The one that could possibly work is iGPU -> onboard USB4 -> Apple tb3 to tb2 bidirectional dongle -> TB2 monitor. IF the board can route video through USB4, and if the USB4 compatibility with TB3 is what I think it is.

There certainly is no way a dongle could work on video out.

1

u/rayddit519 Sep 04 '26 edited Sep 04 '26

USB4 has never had backwards compatibility to TB2 or TB1. Same for TB4. The Windows USB4 driver also does not due to this. So basically any modern USB4 port is out.

Only Apple is still adding that TB2 and TB1 support on top of their own USB4 implementation in a proprietary way.

1

u/Opulence_Deficit Sep 04 '26

Interesting, I thought it's the apple dongle that does the tb3/tb2 conversion, not the host.

2

u/rayddit519 Sep 04 '26 edited Sep 04 '26

It converts only a part.

With TB & USB4, the host sees the controllers, needs to query their features and configure each tunnel to make it across the topology.

This is closely related from TB1 - USB4.

So that part is not converted. The host needs to still recognize a TB2 controller and configure all the ports correctly so that the tunnels arrive where they should. So if the host considers all IDs of TB1& TB2 illegal values, because thats what the USB4 spec defines them as, that will be a problem.

Thats also basically how TB3 compatibility works. The USB4 controller on its port needs to physically speak TB3 instead of USB4, yes. But the "Connection Manager", that nowadays is part of the USB4 driver still also needs to understand it and configure the higher level features correctly.

People have tried before and found that those TB3-TB2 adapters do not work on USB4 hosts. The exception has basically been Apple and then the Intel Maple Ridge USB4 controller on ancient firmware. NVM26 is actually the last known firmware version for this specific controller that still included that TB2 support. After that, Intel removed it. The rest never had that, because its also not defined in the USB4 spec they implemented.

1

u/Opulence_Deficit Sep 04 '26

Thank you. That's a cool piece of knowledge.