This paper presents a synthesis of recently developed swarm algorithms known as Salp Swarm Algorithm (SSA), Grasshopper optimization Algorithm (GOA), Whale optimization Algorithm (WOA), and Grey Wolf optimizer (GWO) for an optimal design of the Proportional Integral Derivative with Filter (PIDF) controller for the Load Frequency Control (LFC) of interconnected power systems.Investigations have been carried out on three areas reheat thermal system with the consideration of the Generation Rate Constraints (GRC) and Governor Dead Band (GDB) for more realistic study. The Integral of the Squared Error (ISE) and the Integral of the Absolute Error $(L4E)$ have been used as a performance index. The effectiveness of the investigated algorithms been examined through a load disturbance in the first area. From the obtained results, one can conclude that all the transient responses almost converge to the same values.