Okay, good to know same issue on also other sp4 models
Definetley related to screen, the noise changes charachteristics to more intensified when touching the screen, e.g. scrolling. Haven't actually seen any flicker lately after last firmware update, altough noise is still there - have to be pretty close approx 10 cm to hear it.
I will return it if they can't fix it with firmware update before end of january.
SP3 does not have this noise, I find sp3-i3 is completley silent (if fan is off which is valid for most normal cases)