I have a new Dell Inspiron 15 7547 laptop here. It makes an annoying high-pitched buzzing sound whenever on AC power.
This is not HDD noise (there's a separate, usual sounding HDD noise when the HDD is working). It's not fan noise (that's also present and it's different and quieter). It's not from the speakers (doesn't respond to volume control).
The buzzing noise is correlated with CPU usage: low CPU usage = loud noise; high CPU usage = no noise. For example, continuously scrolling in the browser will shut it up.
I know that electronic components can make a noise, and I believe this is that.
Question: Is there anything I can do to shut it up?
The buzz is just as loud as the HDD noise but it never stops and it gets really annoying.
Best Answer
As noise is connected to the load (and thus current consumption) this might be case of noisy DC-to-DC converter whose switching frequency falls into audible range.
It is hard to tell whether it is serious or not but I would definitely look into replacing the laptop if it is in warranty as big shift in DC-to-DC switching frequency quite often can have impact on voltages it generates. Even if currently it works fine, long-term you might find some of more sensitive components just dropping dead one-by-one.