Essentially, coil whine is the audible effect of components vibrating, especially when under high load / high power. It can sound like a whine or a rattle or a vibration. This happens with many components, but often it's not loud enough for us to hear or at a frequency that we don't hear well. These two pages have more explanation and some tips to reduce the effect: Unfortunately, you may not be able to eliminate it to your satisfaction. Much depends upon how you use your computer, the acoustic qualities of your room, other ambient noise, etc. I once had a Netgear router whose coil whine was particularly annoying to me. I found that the volume varied among units of the identical model. I tried two or three other units of the same model in the store, and found one that I couldn't hear. Even though they were the same model, same components and power supply, two or three of them were loudly annoying to me, but the last one was inaudible.
I've bought used Dell precision 5530 (pre-lease) and I'm facing issue with something I found has a name "coil whining". It appears after every action on laptop (scrolling, page refresh, vides watching etc) is being made. I've been surfing the Internet/ youtube vidoes but haven't found strict response if this problem can be fixed/ limited somehow.  Some say usage of thermal paste on CPU/GKU can help, others to replace the motherboard and others it just can't be fixed. Can someone clarify the problem for me?
Dell precision 5530 - Coil whine issue