It keeps your processor from melting. Do not run a PC without a heat sink on your processor. Processors can get to extremley high temperatures. The heat sink absorbs this heat and removes it using a fan.
Blow On It
The fan and the heat sinks mounted on the CPU cool it. There is also temperature monitoring circuitry in the CPU which can be watched so that the machine is closed down if the temperature exceeds a threshold.
to modify the clock speed as needed to reduce power consumption and heat.
The Central Processing Unit (CPU) creates heat as electricity is used in processing data. The longer the processing takes place, the more heat is created. Heat-sinks and fans are used to cool the CPU and motherboard, so avoiding, as much as possible, overheating and components burning out.
Keep it clean.Dust buildup on the heat sinks (especially the CPU) can cause it to overheat and potentially do permanent damage.
Assuming the heat sink is on tight enough that you would even consider prying it off with a screwdriver, prying would exert excess stress on the CPU die, and cause it to crack.Typically, a flat-head screwdriver is too wide to safely remove a heatsink from the CPU and therefore the CPU could become scratched or damaged.
Fans and "Heat Sinks" are both necessary to prevent computers from overheating.
Cooler
heat sinks
A CPU socket is a mechanical connection. Its main function is to serve as a connection that holds the CPU and allows it to communicate with the motherboard.
Heatsink compount or special heat pad. The reason for this is to form a tight thermal bond between the processor (CPU = Central Processing Unit) and heatsink for the best transfer of heat away from the CPU.
Most heat is dispersed from the CPU by the heat sink - a large aluminium blob stuck onto the actual CPU. The fan is there to assist in the distribution of heat away from the CPU and into the surrounding atmosphere. So CPU's run so cool - laptops, phones etc, don't have a fan as the CPU's run relatively cool, and the heat generated can be dispersed by convection.