If you build your own computers then you know that you have several types of CPU cooling options available. The most affordable and therefore the most common CPU cooling technology is the heatsinks and the fan. Although there are also some more exotic options available, such as liquid, and Peltier ('active') coolers.
ExtremeTech has done a great article on horizontal coolers. These are basically heatsinks and fans taken to its next logical level. Here is an except from the article that explains more, "Most factory CPU coolers blow downwards directly onto the CPU or heat spreader. Horizontal coolers elevate the heatsink radiator fins away from the base, directing airflow either toward the chassis exhaust point or channeled to help cool other motherboard components like the northbridge chipset, memory, or voltage regulators. Also, many of these coolers can be used without a fan. If you don't have a scorching hot CPU and don't plan to do much overclocking, some horizontal coolers can easily transform into silent passively-cooled solutions."