The King of top down cooling: Thermalright SI-100 SFF Cooler Review Recently I tested DeepCool's entry into top down cooling with the AN600. Today's review we'll be taking a look at Thermalright's SI-100, another top down cooler for SFF builds. This unit features six staggered copper heatpipes and a thicker heatsink than its competitors paired with a full size 120mm fan, which allows it to outperform all of its competitors and claim the title of the king of top down cooling.