The best cooler for the central processing unit (CPU) in your computer will depend on the CPU you have in your computer and how hot you tend to run it. Unless you are using a liquid cooling system inside your computer, your CPU cooler will likely involve a heatsink and a fan to disperse the heat transferred to it. You should look for a cooler that will provide the amount of cooling you require, and will hopefully not be too loud. The best CPU cooler for your needs should also be able to effectively clip onto your CPU without damaging the processor.
The CPU inside a computer works as the heart of a computer, regulating all other systems within the machine. This typically produces heat, however, and so some form of CPU cooler is needed to keep it from literally burning out. With previous generations of CPUs, a heatsink was often all that was needed to disperse the heat away from the CPU. Today, however, a CPU cooler will usually require a dedicated fan to further assist the heatsink in heat dispersion.
A heatsink is a fairly small device installed directly on top of the CPU. It typically looks like a metal block, with a thick flat base and the rest of it divided into individually sliced plates or pins. As a CPU cooler, the heatsink works through heat transference; it touches the CPU and heat is transferred from the CPU into the heatsink. The design of the heatsink, with individual plates or pins, allows air to pass by and transfer the heat from the heatsink itself into the air, which is then pushed out of the computer tower by fans built into the tower.
Most CPUs today run quite hot, especially if they have been overclocked by a manufacturer or user to be more powerful, and a heatsink will now usually use a fan as well. Some systems use two fans, though one is often all that is necessary. The fan on a CPU cooler system should be powerful enough to effectively cool the CPU being used, or it may lead to poor performance and computer crashes. There are a number of websites for CPU cooler manufacturers and computer enthusiasts with reviews of different types of cooling systems and recommendations of different systems.
Different types of heatsinks can attach in different ways, and you should be sure that any heatsink you purchase can properly attach to your motherboard and CPU. Some heatsinks can also be a bit too large and may damage your CPU during installation, so look for user reviews to ensure you will not likely have that problem. You can also consider a liquid-based computer and CPU cooler.
A liquid cooling system can often be a more expensive cooler, but it is also usually more effective. As a conductor of heat, liquid is typically superior to air, so the liquid system is able to pull heat away from the CPU much more efficiently than a standard heatsink. These types of systems may not be necessary for most home computer users, but those running more powerful machines may want to look into them.