When you first connect the power supply to the socket I was frightened because I perceived a very high, low, continuous beep (head right next to the power supply).
In only 20cm distance but this was no longer perceptible. In operation fan noise drown out the sound many times.
The whistling sound is still there even after prolonged operation, for me but not a reason to reduce the rating.
I mention this for people who might react very sensitively to high-pitched sounds.
