The importance of this research is to explore and discuss the effects of rounding the top corners of electronic components which are subjected to a cross-flow and a perpendicular impinging jet on the cooling efficiency. Simulations were performed at a cross-flow Reynolds number of 3410 and three different impinging-to-cross-flow Reynolds number ratios (α=0.5,1and1.5). Four cubic geometries, based on the radius of the top corner, were investigated. The principal aim of this study is to find out the effects of the rounded corner on coherent structures and cooling improvement. The Shear Stress Transport (SST) K–ω model is implemented. Moreover, the assessment of this simulation is investigated by comparison with available experimental data. It should be emphasized that the high mesh resolution was handled where the wall-normal coordinate value is suitable (herein 0.01≤y+≤0.19 for the cube wall). The obtained numerical results are in good agreement with the experimental data. The flow features and coherent structures developed closer to the components considerably influence the wall heat transfer. Additionally, it is found that rounding top corners of the cube can improve the cooling efficiency for α=1and1.5 by more than 6% and 23% respectively when compared to a regular cube.