Buying fan for the CPU is very important than the other components, buying and fixing a fan on the CPU is very important task will build a Computer System.

A heat sink is a metallic device that sits directly on the CPU; its work is drawing heat away from the chip into its cooler, which is made up of aluminum or copper, and having fin-like Structure. The CPU fan attaches to the heat sink, pulling air through the fins; means CPU fan indirectly cools the processor.

CPU fan comes in a variety of sizes and having normally copper or aluminum heat sink with them. CPU fan and heat sink have also indicated with which processors it is compatible with, or rated to cool.

Processors which are sold with heat sink and CPU fan, having normally 5-year warranty. If processor sold without it, carry one year warranty. Inadequate cooling can drastically shorten the life of CPU. So preferably buy bundle of them, manufacturer know more which fan shoot the Processor requirements.

Overclocking the CPU makes them work faster than the manufacturer default setting. Thus chips run hotter than normally, so the proper requirement of fan and heatsink is must that also work’s while overclocking the CPU. Such type of heat sink is normally taller than the average one, and CPU fan have more power and less noise than the commercial one.

Before purchasing CPU fan and heat sink, measure the available space inside your computer case. Advanced heat sink design very tall, not all computer cases can accommodate all models.

Buying CPU is almost the first task to do, while building a computer system. CPU comes with different features; choose CPU as per the requirement. CPU is head of the Computer System, such like brain which is a head of the human body. Different Companies offers different types of CPU with different speed and different features.
As speeds of the processor are progressed into the gigahertz range, naming scheme became inscrutable. Today, comparison between processors is done with the higher clock speed. You need to weigh the processor by processing cores, system bus speed, and amount of level 2 that is (L2) cache, and also determine whether you want 64-bit processor or 32-bit or need to overclock your CPU.
Some of the CPU manufactures are listed below,

1. Intel
2. AMD
3. Cyrix

Few of them are listed below,
INTEL Family,
Pentium - The 80586, or P5, the Pentium is the generation above the 486 processor line.
Pentium Pro - Chip designed to help speed up Windows 32-bit software
Pentium with MMX – It is an processor which having additional 57 new instructions and enhanced speed to graphics and multimedia software. Now a day’s MMX is included in all Intel processors, which has been released after this processor.
Pentium II / III – It is the first of the Intel processors that include the Slot adapters.
Intel Coppermine – It is the Socket (FC-PGA) version of the Intel Pentium III / IV.
Intel Flip Chip – Or name for Intel Coppermine.
Intel Celeron – It is a low end Intel processors designed to keep the low prices of the computers by reducing or at first eliminating the level 2 cache.
Pentium IV - The next generation processors, these processors were over 1GHz and were the FPGA processors.
AMD family,
AMD K6-2 – It is an Socket 7 processor which comes with the 3DNow! technology and first to have the 100MHz bus.
AMD K6-3 - K6-2 chip with Level 2 cache memory that runs at the speed of the CPU.
AMD Duron - Like the Intel Celeron, the AMD Duron is an affordable solution processor allowing drop in the price for the computer system.
AMD Athlon - AMD generation with features such as the 200MHz bus speed
AMD Thunderbird – It is the latest AMD processor, this processor is the socket version.