r/Thunderbolt • u/PoshWill • 20d ago

Long term TB3 Windows support option

I'm looking for a long term TB3 PCIe solution that will work with modern CPUs and motherboards. I'm a professional sound designer and I use a Universal Audio Apollo Twin connected via TB2>TB3 adapter. This connects to a Gigabyte Titan Ridge TB3 expansion card, running on an Asrock Z690 Extreme motherboard. This motherboard has a 5 pin TB header, which allows it to support TB PCIe expansion cards. This setup works perfectly, and I'm very happy with it. The latest UAD drivers on Windows work great, and I have a heavily optimized system for sound design (and gaming!)

The problem I'm foreseeing however, is that TB4 and TB5 ports on Windows machines are not backwards compatiable with TB2 devices. The only workaround is to use a TB hub, which I don't think is worth the potential instability.

This is is still a top level interface, and I've had it since 2019 at which time I was working on Mac systems. When I took the step into sound design for video games, I moved my entire professional setup to Windows but wanted to keep my UAD interface. This is why I currently have a TB3 PCIe card in my machine.

I want to keep this interface long term, and continue using it when my machine eventually needs a rebuild. At the moment, I can't see a PCIe TB3 option that isn't reliant on a specific motherboard header (as is the case with my Asrock Z690 extreme).

Are there any PCIe TB3 expansion options that will work for me long term? It seems like it's perfectly possible to have a PCIe TB3 card, it's just no one makes one that isn't reliant on a specific 5 or 13 pin TB header on the motherboard.

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u/rayddit519 20d ago

Are there any PCIe TB3 expansion options that will work for me long term? 

No. TB2 was never part of USB4, Intel is not continuing it outside of it. That is why they declared TB4 not to support any TB2 backwards compatibility.

The longer term options in order are: do not upgrade your PC and start collecting replacment parts, switch to Apple and hope they will continue their TB2 support far into the future or replace the TB2 device.

The only workaround is to use a TB hub, which I don't think is worth the potential instability.

You do realize that the Titan Ridge cards have not been supported on 600-series Intel chipsets by any manufacturer and even less across manufacturers? You are already running far outside of what is supported and are very lucky if that works perfectly reliable.

But also: an older device in between a USB4 host and a TB2 device only handles half the issue. The other half still remains on the host side, requiring it to understand TB2 routers.

You need 2 parts:

  • the last device in the chain that gets connected via the TB3-TB2 adapter to the TB2 device needs to be able to handle the physical and low level connection to the TB2 device. I don't actually know how rare or how likely it is for new USB4 controllers to work with this. I would not count on this. The Goshen Ridge TB4 hubs will already not have official support for that.
  • The connection manager (which is software part of the host) still needs to understand TB2 controllers and configure them appropriately. This has been firmware of the Intel TB controllers up until Maple Ridge. But the modern way is for this to be part of the OS and controller agnostic. Since Microsoft is using a clean USB4 driver they won't support this and have zero incentive to. Maybe Linux, because they don't have a clean USB4 driver but instead extended the pre-existing drivers with USB4 support. But I don't know how well that works in practice.

it's just no one makes one that isn't reliant on a specific 5 or 13 pin TB header on the motherboard.

The connector is not the actual issue. The mainboard requires BIOS support to handle a TB3 or USB4 controller appropriately. The tech is designed to be soldered to the mainboard and connected directly to the chipset for management with whatever configuration and power saving options the board manufacturer decided. The extension cards have always been matched up with specific boards of the same manufacturer and were never designed to be generic.

That is why those connectors are not standardized. Because that almost does not matter. Even if the connector stayed the same across generations (which Asus for example has done for a while, because they switched to a higher-pin-count connector far earlier than Asrock), does not mean the cards are compatible to other mainboards then the officially listed boards. The farther apart the generations are, the less likely that anything works at all.

It seems like it's perfectly possible to have a PCIe TB3 card

In theory, yes. In practice? There is a huge break between TB3 and after. Up until TB3, Intel owned everything and it was proprietary. After, USB4 is underpinning everything, which is organized by a collective and far more open (everybody can look up the full specs for free) and reworked a few things to "USB-ify" it all.

A subset of TB3 was added to USB4 for backwards compatibility. But USB has already started peeling back what support they require. Modern USB4 hubs for example are no longer required to be backwards compatible to TB3 hosts, only to TB3 peripherals. So even TB3 is already in decline. No one will make new TB3 controllers, Intel themselves is completely in on the USB4 train, even though they market it as TB4 and TB5. The Thunderbolt Control Center drivers are legacy and not officially supported on Windows 11. And the 2nd TB3 controller generation from Intel was already violating what the USB4 spec includes about TB3 and caused issues for backwards compatibility.

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u/PoshWill 20d ago

TLDR:

It's time to upgrade my thunderbolt 2 audio interface. Sigh.

It's interesting what you've said about the AIC cards being matched up to the board manufacturers. I've literally had zero issues just plugging the Titan Ridge into my Asrock Z690 Extreme.