I boughtt an Enermax 430W unit for my HTPC last year - and have spent a few hours tryng to make it more quiet. It certainly is not the most quiet PSU I've ever had. Reliable, yes. Powerful, yes. Well built, yes. Quiet, not really. The Directron.com forum boards suggest that I'm not the only one to find this, but others think that they are quiet. Go figure. I'm guessing that it depends on how much juice you're trying to pull out of it.