Plenty of numerical or experimental studies have been devoted to the hydrothermal characteristics of heat sinks with multiple vortex generators (VGs). In this study, in order to boost the heat transfer rate and reduce the hydrodynamic dissipations, VGs are chosen to have flexible splitter on their lee sides. Also, VGs are selected at different axial and transverse inter-distances. The Reynolds number, based on the channel's hydraulic diameter, is set to 1000 to ensure laminar flow. The heat transfer performance, the hydrodynamic friction factor and the overall hydrothermal efficiency for different number of VGs and splitter's flexural rigidity are investigated. The results showed that flexible splitters provide better heat transfer capability and the higher hydrothermal performance compared to rigid ones. The results also indicated that, by selecting proper configuration, in the expense of 10% decrease in total hydrothermal efficiency with respect to clean channel, 190% increase in the rejected heat can be achieved.