StarTech.com silver thermal transfer compound improves the effectiveness of CPU coolers by thermally bonding the CPU to the heatsink. StarTech.com chose this substance to put into the heat-grease because silver is one of the best conductors of heat known. This ensures that the heatsink and fan can work at their full capacity to remove the harmful heat away from the CPU, and prevent burnout or heat damage. Silver grease is twice as effective as standard silicon-based heat-grease.