what are your ambient room temperatures? My $60 Zalman CPNS9500 kept my 3700+ stock around those temps in a warm room, cooler, more "normal" room was 38C. Now I'm OC'd and in a really warm room (talking almost 26 degrees C) it peaked out at 48C or so.
If you are in a 15C room and your temps are like that, I'd be checking stuff. Did you use AS5? A massive cooler won't do much good if there isn't enough airflow in the case either since it would just recirculate warm air. I have a 140mm fan in the back of my case
