Optimum max CPU level

I’m wondering what the optimum max CPU level is when no audio is passing through.

If I build a pedalboard that uses about 90% of the CPU then start playing I notice that It will hit 100% very quickly when I start playing.
Is there a safe level I can build the pedalboard to before playing through it?
What level do you suggest?

Are there certain effects which increase CPU usage more than others when passing audio?

Thank you for your support!

I think the sweet spot is usually at 80%.
If we max out the CPU, regular tasks like saving will take longer (keeping the audio running is #1 priority).

There are definitely plugins that use more cpu than others.
It depends on what they do internally and how well optimized they are for ARM.

I was thinking 80% is about the right place.