Since we're talking PSU's I'll chime in. I remounted the 120mm fan on my 400w aurora on the outside of (the bottom of) the psu case. The extra air gap improved airflow enough to slow ramp-up under load.
I had also swapped my radiator and its fans (they are the intake for my case) and the extra airflow (even at the low noise level I wanted) further kept the PSU fan from ramping up.
Ducting fresh air to the PSU would probably make it even quieter.
I found these threads useful:
http://forums.silentpcreview.com/vie...=16393&start=0
and
http://forums.silentpcreview.com/viewtopic.php?t=17002