TGILLITZER,
Have you NEVER heard of heat reflectors ?? Go and read your science books. Heat is easily reflected between the heatsink and the copper shim. The ceramic base of TBIRD/DURON is designed to ABSORB the heat and carry it to
the bottom of the package. While its true that heat is energy, the design of any heatsink is to absorb the energy and then dissipate the energy into the air. Don't take my word for it, E-Mail AMD, they will tell you NOT to use copper shims