It's so quiet that during the day u can't hear it. Fans spin 500-600rpm. I have aquaero set up so the fans spin based on water temp.
Even now with the hot weather, water temp is around 30-34°. Cpu usually tops at 60-70 and GPU is 40-42° (that's overclocked to 2100mhz on the core)
In the evening when it's very quiet I can barely hear the pump