I have drastically reduced the noise my fans make (the PSU and motherboard fans), by swapping them for quieter ones as described in this community Facebook post:
https://www.facebook.com/groups/cr6community/permalink/918853728641019

Hi, I've just received my printer, but the moment I turn it on the fans are loud and constantly running. Is this normal?

The nozzle and heated bed are off, and the only option I can find in the menu is via Control -> Temp -> Fan. I can hear a fan turning off somewhere (where out of interest?), but the extruder fan remains on.

I've updated to firmware v1.0.2 but that didn't help.

Also, how do I search these forums, in particular this category please?

Thanks.