Signal integrity analysis
In high-end designs, high speed behavior often affects more than 80% of the signals on the board.
Transmission line behavior is complex, and simulating it is essential to get an understanding of signal behavior. Manufacturing tolerances of various components must be considered in the simulations, for the combinations specific for the design.
Investigating signal integrity in any step in the design process gives insight in how everything on board influences the outcome. This way you can take out signal integrity issues before the PCB goes in production.