[rayiner]

Sure, but how big of a difference is there? Even inside a desktop PC, you typically have PCIe ports directly off the CPU and ones off the chipset, and the latency for the latter is double. But the difference is immaterial in practice.

[washadjeffmad]

I think latency is the wrong focal point (more important for gaming, plus Macs don't support eGPUs anymore). There aren't a lot of general workloads that require high sustained throughput, but the ones that do can benefit from TB5 scaling.

For instance, if you cluster Mac Studios over TB5 with RDMA, the performance can be pretty stellar. It may not be more cost effective than renting compute for the same tasks, but if you've got (up to) four M3 Ultras with a ton of RAM, you'll be hard pressed to find something similar.

That's still not more ideal than having native alternatives like OCuLink or something that can be networked like QSFP, but it's a fair way to highlight the current design's strengths.

[angoragoats]

GPU performance can be perceptibly slower with TB5 compared to Oculink. Here’s one article showing a 14% difference in one test setup:

https://www.tomshardware.com/pc-components/gpus/oculink-outp...