Does macOS 26.2 support RDMA connections over Thunderbolt 4?

snoopyf15e wrote:

Does macOS 26.2 rdma support connections over thunderbolt 4?

[Re-Titled by Moderator]

Original Title: macOS 26.2 RDMA question

re: < thunderbolt 4 > No.

note:

Thunderbolt 4 (40 Gbps)

Thunderbolt 5 (80 Gbps w/ peak speeds up to 120 Gbps (Oct 2024 M4-MBP and Mac mini/Mac Studio 2025)



I see no documentation from Apple beyond the announcement

macOS Tahoe 26.2 Release Notes | Apple Developer Documentation

however you can search—

https://appleinsider.com/articles/25/12/20/ai-calculations-on-mac-cluster-gets-a-big-boost-from-new-rdma-support-on-thunderbolt-5

further—

Call Customer Support (800) MY–APPLE (800–692–7753)

or on line https://getsupport.apple.com/

Outside the USA—Contact Apple for support and service by phone

See a list of Apple phone numbers around the world.

Contact Apple Support - Apple Support

this pull-quote suggests (but does not state decisively) that it is NOT supported under Thunderbolt-4:

The massive bandwidth is especially useful thanks to Apple's inclusion of RDMA (Remote Direct Access Memory) in Thunderbolt 5. Under RDMA, one CPU node in the cluster is capable of directly reading the memory of another, expanding its available memory pool to incorporate others in the cluster.

from:

https://appleinsider.com/articles/25/12/20/ai-calculations-on-mac-cluster-gets-a-big-boost-from-new-rdma-support-on-thunderbolt-5

Yeah, that would mean I could upgrade my M2 Max keep both machines working together. It's a shame that it doesn't seem possible yet :(