Abstract In this study, impingement/effusion cooling with cross-flow of in-line array of electronic components (ECs) is investigated numerically using RNG k-ɛ turbulence model. The cooling process is examined for two channel base configurations i.e., solid board (SB) and perforated board (PB). Effects of effusion perforation diameter (d/l) and its position (s/l) are considered on flow structure, temperature contours, heat transfer, and friction coefficient for different jet-to-cross Reynolds number ratios (ReR). Throughout the experiments, the jet position is kept at the third EC [1] . The results show that utilizing perforated board generates a new E vortex behind each component and the magnification of the wake vortex depends substantially on both perforation diameter and position. The ratio of average heat transfer coefficient ( h ¯ R ) on the rear faces of ECs decreases with increasing s/l; while, it increases with increasing d/l. As well, d/l has a significant effect on friction coefficient; while, ReR and s/l have inconsiderable effect. Furthermore, the highest value of performance evaluation criteria (PEC) that is accomplished at the largest perforation diameter for the closest one, equals to 1.36 at ReR of 0.5. Also, a proposed correlation is presented to estimate PEC for PB as a function of ReR, d/l, and s/l.