A scheduling model is studied where the computing time function of each node is a nonlinear function of the size of its assigned load. Speedup and closed form solutions for optimal load allocation are obtained for simultaneous load distribution. An iterative solution technique is presented for sequential load distribution. Super-linear speedup is possible when the computing time function is a nonlinear function of the amount of fractional load assigned. Index Terms Divisible load scheduling, Store and forward switching, Multilevel tree network, Nonlinear Computational Loads, Speedup.