A method and system for performing analog and RF simulation is disclosed that balances the need for accuracy with the desire for increased simulation speed by using two different circuit descriptions, one description is used during the simulation where needed for accuracy and the other circuit description is used where needed to speed the simulation. For example, one circuit description may include parasitic information and is used where necessary to maintain accuracy and, whereas a reduced circuit description (with at least some parasitic information removed) can be used to enhance speed. This combined solution that uses two different, but related, circuit descriptions has substantially increased the speed of simulation with minimal sacrifice of accuracy.