Well, maybe that's why your last one fried - perhaps the PSU's fan bearings were worn out causing the fan to slow down gradually and eventually seize. You might hae got used to the quiet - then it burned up. The new PSU's fan noise may now be normal, yet seems loud in comparison. Let's hope because you might have got a new PSU with a bad fan.
Or something else is going now. What kind of noise is this? Is it mechanical like the vibrating sound of a motor wearing out? Or noise of lots of air moving through fast turning fans blades? Or something different?You need to poke your head inside and see what's making the noise if you feel it is more than just more air movement. If you can see the center hubs of the fans, touch them for second. You will be able to tell from the change in pitch of the fan noise if that is the offending fan. Stick your ear to the back of the PSU to hear if the louder than normal noise is coming from it.
