The last thing I'd check would be the farthest right connector on the micro board, that routes back to a header on the motherboard which will be marked as one of the above.
It needs to be plugged into CPU_Fan preferably, but at a pinch SYS_Fan.
If it's plugged into CH_Fan, then that's the problem, it will be running all the case fans at full tilt.
Oh.... is it a case fan that's causing the noise? I had been working under the assumption it was a radiator fan