The paper deals with the speed up of a computer program, which simulates rolling of steel with semi-solid zone. The mathematical models describing the rolling process are fully three dimensional. It leads to very long computation time while the discretization of the problem is made in finite element manner. The main objectives of the contribution are optimization of the program code, as well as making of the first look at possibilities of parallel computation in application to the presented problem. The paper has proved that efficient optimization of the program code can lead to significant shortening of the computation time also with the automatic and manual parallelization. It was concluded that adaptation of the procedures and loops to rigorous requirements of the parallel compiler is strongly recommended.