A mechanism for improving speed of simulation of complex circuits that include transistors and other devices that share similar properties is provided. Circuit simulation speed is improved by efficiently identifying transistors and other devices having identical properties that share a same state at the time of interest in the simulation. Transistors and other devices are collected into groups having the same characteristics and topologies prior to simulation. Then during simulation, a determination is made as to whether a previously-evaluated transistor or device in the same group as a presently-being evaluated transistor or device has terminal input values that are the same, or nearly the same. If so, then output values of the previously-evaluated transistor or device are used in calculating the output values of the present transistor or device.