Since I have the Fractal Design Define R4, where even 2 of these fans were installed.
I knew where I was letting it at 5V are not listening as 7V.
In absolute silence I hear only slightly my ASUS Radeon R9 290th
Only at 12V hear airflow but no chatter or the like.
I have the fan installed in the front of my tower (as second).
My ASUS Radeon R9 290 was before him always in IDEL so at 43-45C °,
now only at 37-40C ° My Xeon is as fallen from 20C ° to 18C ° IDEL.
I can only recommend one of those fans.
PS: I felt in my server a 120mm be quiet Silent Wings 2 and is loud!