How dose a gaming system use multiple GPUs? I thought this stopped. I tried to look it up, but the applications for multi-GPUs today are for machine learning.
The Path Tracer in Unreal Engine 5 is basically for offline rendering it isnt actually for gaming. (atleast not yet, with more powerful GPU who knows)
Remember that Unreal Engine at this point is much much more than just a gaming engine.
You can use the Path Tracer to do Light/Shadow mapping, ground truth renders or when you need to render out cutscenes/movies.
Most if not all GPU render engines will utilize all GPUs in a system even without the interlink.
Unreal Engine 5 prior to V5.1 would basically ignore the other GPUs in your system.
With this update I guess it will utilize them.