I have the same issue on my NUC5i3RYK - but in my case it starts to whine more when installing updates... but there is always a little whine... contacted the intel support, but no answer.
I don't know if this will solve the issue. With my NUC "K" I had a tiny, baby rattle sound esp. while paging thru a web site. After trying various tweaks, I unchecked the hardware acceleration in Firefox. I also unchecked the auto and smooth scrolling. No more audible baby rattle sound. Maybe its just quieter.
Thank's but my problem occurs even with no activity (Linux Mint with no program running).
Could you please provide us with more details as to when and how this sounds happens.
Besides testing the system without SSD could you please confirm if you have tested different RAM Memory?
Also please confirm which is the specific BIOS version your Intel® NUC is Running?
I didn't test different RAM memory because I have only one : a crucial 8Gb.
My bios version is the last one : 350.
I bought a new NUC5i3RYK for testing and the bios version was the first built-in. And the problem was the same : a low coil wine from the processor.
But I can hear this annoying sound only if I take the motherboard out of the NUC case with the fan disconnected or if I put it into my akasa fanless case (It's true it's a low noise but in a fanless case, it's a really annoying shrieking noise).
So I think it's not a misfunction of my NUC5i5RYK (I didn't receive a new one yet but the NUC5i3RYK has the same problem).
It would be great if any bios setting could improve this issue.
Thank's for help.
We continuously strive to improve the quality of our products to better serve our users and appreciate feedback on any issues you discover and suggestions for future BIOS releases.