I used to have the same cooler, with a 3.3 overclock I ran it at about 1700rpm for normal operation, but anytime I used any processing power I ran it at 12v. Under load, at 12v, It still got up to about 52c.
Replaced with the 9500 and temps dropped 10c. I've got it running through the motherboard speed controller right now, so I haven't charted fan speeds yet, but I rarely hear the fan ramping up to full RPMs.
-z