





I found some conflicting information regarding the Infinity Fabric Link hardware for the AMD Radeon Pro Vega II Duo. I feel fairly confident in the conclusions below, but I would love some further input from the community.
The GPUs in question are:
- AMD Radeon Pro Vega II
- AMD Radeon Pro Vega II Duo
- AMD Radeon Pro W6800X
- AMD Radeon Pro W6800X Duo
- AMD Radeon Pro W6900X
The Infinity Fabric Link parts in question are:
- Bridge A2326
- Jumper A2329
- Bridge A2666
- Bridge A2667
- Jumper A2668
The Jumpers are straightforward. The Duo MPX GPU models are the only ones that use them, since their purpose is to link the two GPUs inside a single MPX module.
- A2329 supports the Vega II Duo only
- A2668 supports the W6800X Duo only
The Bridges are where the conflicting information appears.
From what I have found:
- A2326 supports the Vega II only
- It does not support the Vega II Duo, W6800X, W6800X Duo, or W6900X
- A2666 supports the W6800X and W6900X
- It does not support the Vega II, Vega II Duo, or W6800X Duo
- A2667 supports the W6800X Duo only
- It does not support the Vega II, Vega II Duo, W6800X, or W6900X
Apple’s documentation clearly states that the Vega II, W6800X, and W6900X support an Infinity Fabric Link Bridge. For the W6800X Duo, Apple’s documentation states support for both Jumper and Bridge.
However, Apple’s documentation only mentions the Vega II Duo using the Infinity Fabric Link Jumper, not a Bridge. Apple even shows two Vega II Duo modules installed in one 2019 Mac Pro, but only shows the Jumpers, with no Bridge, despite it being a dual-Vega II Duo setup.
This also lines up with the box contents. The W6800X and W6900X ship with their corresponding Bridges, and the W6800X Duo ships with both its Jumper and Bridge. The Vega II Duo only ships with the Jumper. I have confirmed those box contents myself. I have also read that the Vega II ships with Bridge A2326, but I have not personally confirmed that.
So where does the conflict come from?
My best guess is that it comes from a mix of assumptions, the fact that the A2326 Bridge physically fits the Vega II Duo, and third-party listings; especially MacSales / OWC stating that Bridge A2326 supports the Vega II Duo.
MacSales’ A2326 page is one of the first results that appears when searching for the part number. I was one of the users who saw this, believed it was true, and shared that information with others. However, based on Apple’s own documentation, the observed box contents, and other online data points, I now believe that the compatibility claim was a mistake.
What would happen if the A2326 Bridge is connected to the Vega II Duo?
First of all, it would physically fit. But after that, macOS would simply fail to boot. My best guess is that it would be similar to the problem Linux users are currently facing with Infinity Fabric Link, including psp -20 errors or BAR size issues.
To summarize support, my current understanding is:
| Part | Type | Supported GPU |
|---|---|---|
| A2326 | Bridge | Vega II only |
| A2329 | Jumper | Vega II Duo only |
| A2666 | Bridge | W6800X / W6900X |
| A2667 | Bridge | W6800X Duo only |
| A2668 | Jumper | W6800X Duo only |
Back to Linux and using the Infinity Fabric Links, this raises the question:
Is this why some Vega II and Vega II Duo users have fluctuating success with Infinity Fabric Links?
Vega II users with the Bridge would succeed, while Vega II Duo users with the Bridge would experience errors. On the other hand, Vega II Duo users with the Jumper would succeed as well.
If you are a Linux user with a Vega II or Vega II Duo, and you have tested either the Jumper or Bridge, please share your experience.
One remaining [For Fun] question I have, for both macOS and Linux users:
Would the A2666 Bridge work with one W6800X and one W6900X?
This is interesting, because A2666 is the only Bridge associated with two different MPX GPU models. However, Apple’s documentation seems to describe it only in same-model configurations: two W6800X modules or two W6900X modules.
So my assumption is that a mixed W6800X + W6900X setup is probably unsupported in macOS, but I would be interested to hear from anyone who has physically tested it.
I would also be interested to hear from anyone who has physically tested the A2326 Bridge with two Vega II Duo MPX modules, since that appears to be the main point of conflicting information.
Disclaimer: I wrote this post myself. I also used AI as a tool to help clean up the wording and formatting.
References:
- Apple’s Documentation
- Reddit Post
- macOS will not boot (User 01): u/ResortMotor1264
- macOS goes into Recovery Assistant (User 02): u/Malter_Witty
- MacSales’ Apple AMD Infinity Fabric Link Bridge Page
- Attached Images.
- I’ll add more if I get them.