Hi Peter, just curious to know if you used the Audio workgroups thread registration method for your real-time audio threads (for Mac ARM builds)? I did for my plugin and it definitely improved things (but still doesn’t appear to be a way to force threads to p-cores only).
(Awaiting JUCE team to formally bring this to JUCE API - hopefully soon, but there is a least a working solution for AU/Standalone if you check my and other related posts:[MacOS Audio Thread Workgroups - #11 by onar3d]. Maybe the latest VST3 updates now allow to retrieve the audio workgroup - I haven’t had time to check that.)