Today we take a look at the Zalman CNPS8000A CPU cooler. True, OverclockersClub is known for its enthusiast class reviews that can exploit the boundaries of performance hardware available to all who want to push their overclocked computers to the max, but we still have to cater to the needs of the people out there that need specialty coolers for projects like SFF and HTPC case builds. So, for those select  people we will take a look at this Zalman CNPS8000A, sitting on top of an i3 540 processor, because you really don't need an overclocked i7 pumping movies to your TV in an HTPC case. Zalman does state this cooler is compatible with the Intel 1156/1366/775 and AMD AM3/AM2+/AM2 series of processors.Okay, how about a little discussion on air cooling. What do you want an air CPU cooler to do? You want it to remove as much heat as possible, as quickly as possible, from your CPU. Starting at the mating surfaces, you want your cooler and CPU to be as flat and void of imperfections as possible resulting in the greatest metal to metal contact obtainable. Imperfections even down to the microscopic level will affect the transfer of heat between the two surfaces. That is why TIM (thermal interface material) is required when mounting your cooler to fill any imperfections and give you better thermal conductivity between the two surfaces. If no TIM was used, air would be in the voids between the two surfaces and air is a very bad thermal conductor, hence higher temperatures would result.Just for reference, air has a thermal conductivity of 0.025 W/(m-K) versus copper's thermal conductivity of 401 W/(m-K). Quite a difference between the two, so, the smoother and void-free the cooler's base is, the better the heat transfer between the mating surfaces will be. Now you have the heat generated by the CPU being efficiently transferred to the coolers base and in most cases into a heat-pipe array to be carried away from the base of the cooler.But what are heat-pipes anyway? Heat-pipes are pipes that contain a liquid that uses evaporation to transfer the heat from the hot CPU to the coolers fins to be removed by the fan attached to the cooler and then condensation returns the liquid back to the CPU, either by gravity or wicking, to be heated again. Heat-pipes are a more efficient thermal transfer means than even solid copper, that's why it's become very common for heat-pipes to be used on all types of coolers today. This is very generalized and a lot of science goes into the design of modern coolers including the exact make-up of the metals used, fin thickness, fin density, fin angles, base thickness, base machining, heat-pipe diameter, etc., so you can see why two coolers that look very similar can produce very different results.