You can read in various forums (Computerbase, HWluxx) that the fan hums noticeably/audibly. So far from "silent"...
Are there any here who have also noticed this?
I don't think it's loud. I have one, but so far I have not been able to use it because the giant power plug in the BeQuiet case "Dark Base pro 900 rev2" could not be plugged in. In the meantime, I have received an open panel from BeQuiet that conceals the problem. Unfortunately, the power supply also delivers power when the power switch is set to zero. I have therefore bought a great Pro 11 750W and am still thinking about what to do with the other one. I definitely want to use it! I hope this answer helps.