What is normal mode, speed mode, A2 mode, X mode, etc?

Note Series
#1

Hello,

Could you please explain the different display modes in terms of functionality and power consumtion?

I remember there used to be a regal mode. Is that still available? Is it the new normal now or the “speed” mode?

Could you rate the modes in terms of CPU/battery efficiency? Which is the most low-power?

Thanks,
Andrey

#2

My 2 cts: some useful information there => Does the A2 mode reduce battery life?