zlacker

Not nearly as cool as your what you described, but I took advantage of the horrible coil whine on my Dell XPS 15 9560. The Intel CPU, Nvidia GPU, and Toshiba SSD all had different pitches of coil whine. Based on the pitch and volume, it was very easy to tell which component was being stressed :)

>>chenxi+(OP)
I can relate. Around the time I got this tour of the museum, I was working on a rendering algorithm that was slow and could occupy the GPU for seconds at a time. For some reason- whether it was a poorly stabilized power supply or EM radiation I do not know - I could hear pretty loud chirping noises when I had my headphones plugged into the onboard analog jack. It went so far that I could easily tell which part of the algorithm was currently running on the GPU and I could sometimes even count single iterations. This was very helpful because the screen was of course frozen. while the GPU was busy with my program.

This computer finally made me buy an external audio interface out of frustration. I went on to do some acoustics projects and I really needed cleaner audio for them.

>>chenxi+(OP)
I used exactly this phenomenon on my XPS13 to know when my Gentoo was in the "merge" phase of an ebuild (distinctive noise generated by copying a large amount of files).