Cleaning up my gear, I found a bunch of old ICeage 120 HSF (socket 775/939 / AM2+ HSF) https://www.techpowerup.com/review/3rsystem-ice-age/ I think they were the fist direct heatpipe to CPU HSF developed.. Did some investigating to see if I could use it on socket 115x w... no go.. But AM2/AM3 hsf with clips are compatible with AM4.. So.. Fired up the Asus C6H with a 3600.. Clipped on the old HSF... Prime 95 at 75 degrees, (jet engine) Silent at idle.. (DC controlled) - had lost the included fan controller a long time ago.. Lesson.. Don't throw away those old CPU HSF.. they still could be useful..