"Seeing specifications like more than 100 CFM, and almost 2mmH2O of pressure from these 140mm fans, we had a suspicion that things may in fact get loud when let lose at their maximum levels. The 59 dB rating here proves our suspicion, but keep in mind: we forced this result as a worst case scenario. With software control, it is likely you will never get to this level of noise unless you are going all out and need that extra power for benching."
I've never had any noise problem, even while doing benchmarks the sound was never an issue.