Depends on your final goals. You see, with the help of thermal scope you can track down and hit the target in a short time: it perfectly shows animals hidden in trees, in snow, in bushes and even in thick grass. It is the thermal scope that makes hunting much easier and expands the capabilities of a modern hunter. So, I recommend my favorite thermal optics www.atncorp.com/thermal-scope-thor-hd from ATN. Good luck
There are microscopic gaps and crevices that exist on any metallic surface. These gaps are known as contact resistance, and they are filled with air - which has a thermal conductivity of approximately 0.02 W/mK. Thermal paste will typically have a thermal conductivity of approximately 10 W/mK. Copper, on the other hand, has a thermal conductivity of 400 W/mK.
Thus, you can see that thermal paste is substantially more thermally conductive than air (in the gaps between the CPU and the heat sink), but is significantly less conductive than the copper (or other similar metals).