The life of the electronic components strongly depends upon the heat transfer which is generated within that component or the cooling of that device. For this reason the need for forced air cooling is the main factor that should be consider at the starting phase of electronic system design. The one of the critical parts of any electronic device is heat sink, which dissipates heat from electronic device to surrounding. Thus the choice of an optimal heat sink depends upon the number of geometric parameters like fin height, fin length, fin thickness, number of fins, fin materials etc. With the help of commercially available computational fluid dynamics software’s Icepak and Fluent, we can easily analyse the cooling effect of CPU.