A system and method for developing condensed netlists for sub-circuits within an integrated circuit and for modeling the performance of the integrated circuit based on the condensed netlists rather than full netlists. An IC layout is segmented into a plurality of sub-circuits, each comprising a group of one or more of a given type of active devices connected to (i.e., sharing) the same electrical sub-circuit terminals through a similar resistive network (i.e. such that they are subjected to approximately the same overall combined parasitic resistances). Full netlists corresponding to the sub-circuits are extracted from the layout and condensed. Each condensed netlist accounts for performance variations (e.g., as a function of variations in operating power supply voltages, operating temperatures and, optionally, self-heating and/or stress) exhibited by the active devices and resistive network in a sub-circuit. The condensed netlists for the sub-circuits are then simulated over the full range of operating temperatures and full range of operating power supply voltages for the integrated circuit in order to generate a performance model for the integrated circuit.