Hi aadilqau
As far as i have observed the simulation time mostly depends on the power level you are using in your system design.
Try simulating a system with 40 iterations at low power level and compare it with a system with less number of system sweeps but use a high value of power in this case.The simulation time of the first case will be small compared to the second one even when the first case is using large number of sweeps.
Reason being the fiber takes a very long time to allow a high power signal to transmit.
But ofcourse it is not always possible to work at very low power levels just to have a faster simulation.So even if sometimes a system takes long to simulate it is worth to wait to achieve a the required performance.
Thanks and regards