I didn't write down the numbers (cooler was bought during a 2005 CompUSA black friday sale for $5) so I can't give them. As I best I remember the memory modules saw 10c+ drops in temps just from a tiny bit of airflow. The way the machine is built the heat from the DDR2 modules goes straight up into the center of the motherboard and into the chassis... so cooling the memory modules down did affect temps for everything else to a small degree.
Not the best image, but imagine those two memory modules putting out a ballpark figure of 50W of heat. Under the machine, just a few millimeters above a desk. The heat buildup after an hour is incredible. Link to photo