Illumination and temperature non uniformities lead to mismatch losses in dense array CPV receivers. A cooling device, formed by a matrix of microfluidic cells with individually variable coolant flow rate, has been implemented in order to smooth the temperature profile with respect to the illumination one. In this study, once the temperature issue has been reduced thanks to the self-adaptive cooling device, the impact of the illumination non uniformity magnitude on the receiver performance is assessed. For a given electrical configuration, the receiver output losses increase linearly with the illumination non-uniformity.