[jan-jaap]

If you looks at the backside of the machine, you've got CPU etc on the left hand side of the PSU, and on the right hand side you've got a carrier with 4 quadrants where the graphics etc are. If there is anything in the bottom right slot there, it will engage "fastfan" which is infernal.

I see you've got a Galileo video option and a fibre channel card. If you can do without any of those, rearrange things to make sure the bottom right slot is not used. An Octane is never quiet by today's standards, but fastfan is unbearable.