Abstract: Heat sinks are an extremely useful component that helps to lower maximum temperature of electronic devices resulting in an improvement in overall thermal efficiency and performance. Fins form an integral part of sinks. Geometry of fins plays a vital role in heat transfer from sinks. Researchers have studied effects of thermodynamic properties like heat input and base to ambient temperature difference. After experiments some investigators have also developed correlations .While optimising heat sink geometry aspect ratio needs to be also considered which has an important effect on heat transfer. Effect of very low aspect ratio needs to be determined.