I’m not sure all the information in this thread is correct. I downloaded the ue5-main branch last night and built from source (in 2.5h) on my M1 Max. Running the engine, the startup time was still painfully slow with multiple instances of ShaderCompiler pegging my CPU.
Looking in the Engine/Binaries/Mac folder and running file ShaderCompilerWorker shows that most of the underlying binaries of UE5 are still x86_64 not arm64. Which explains why I didn’t notice any improvement on these shader compile times.
Another bit worth noting is that Metal 3 supports shader precompilation for Apple devices which could potentially help this start up time? Though I suppose these shaders are in the Unreal shader format so maybe not.