may we double check if the issue happen when you unplug the AC adapter?
After unpluging AC, noises occurs, but very quiet.
and where does the noise comes from? also close to the fan?
I don't think It come from the fans. It's like close F6 key, or from the back near to the sticker with serial number. (I've record todays noises from the back).
and when your device is idle ( no program on) and just simply scrolling, it happens too?
Today I've noticed when turning on Performacne mode there are constant 'beeping' coming, when moving mouse It changes to 'buzz'...