In the present numerical study, a double-layer microchannel heat sink (DL MCHS) with a series of semi-circular bumps and slits on the side plane wall of both upper and lower channels is investigated for the augmentation of heat transfer. The performance of the proposed configuration o is compared with the single-layer microchannel heat sink (SL MCHS) and parallel rectangular DL MCHS for anticipated results of heat transfer coefficient, temperature distribution, Flow behaviour of the coolant in microchannel and pressure drop. All three heat sink configurations are numerically simulated for the operating range of Reynolds number i.e. 100 − 400 and heat flux varying from 200-500 kW/m² respectively. Performance of the heat sink is also evaluated on the basis of thermal performance factor which includes both; heat transfer rate pressure drop. The comparative study shows that DL MCHS with semi-circular bumps and slits has better potential to dissipate high heat compared to its counterparts. It is due to an increase in surface area to volume ratio and enhanced fluid mixing.