That depends on the amount of data to process and the computational effort involved. Provided a sufficiently challenging task and a fixed amount of computation

That depends on the amount of data to process and the computational effort involved. Provided a sufficiently challenging task and a fixed amount of computational resources you can easily predict the time needed to reach the goal. If the duration is exceedingly large or expensive it might make more sense to distribute the work load. Even though there is a delay to interconnect this delay will not likely reduce the benefits provided by distribution if the decision criteria are costs and expenses over time. These are all things that can be graphed and mapped against financial estimates.