There is no doubt that the miniaturization of various electronic devices, including processors, servers, micro-electromechan-ical system devices, etc. has resulted in increased overall performance. However, there is a major problem with thermal management in these devices, as well as in many others. One of the most promising solutions is liquid cooled microchannel heat sink. In the current work, different cases of open micro pin-fin configurations of heat sink were considered. The con-figurations considered were a uniform height micro pin-fin heat sink, three-stepped unidirectional micro pin-fin heat sink and three-stepped bi-directional micro pin-fin heat sink. These configurations were also oriented in two dissimilar fashions, i.e. inline and staggered, so the total of six heat sink configurations are compared and analysed. Using single phase water as a coolant and copper as a substrate, these configurations were simulated numerically for different Reynolds numbers (10−160) under heat flux of 500 kW/m². It can be concluded that at low Reynolds numbers, steepness does not contribute much in both inline and staggered arrangements, while at higher Reynolds numbers, 3 stepped staggered configurations has revealed the best performance due to boosted fluid mixing and more projecting secondary flow. Furthermore, bi-direction-ality in steepness shows augmented performance only in inline arrangement.