A method begins by a dispersed storage (DS) processing module ascertaining processing speeds of distributed storage and task (DST) execution units where the DST execution units receive a set of encoded data slices that includes a sub-set of data-based data slices. The method continues with the DS processing module allocating task performance on the sub-set of data-based data slices to a sub-set of DST execution units, where a first DST execution unit is allocated to perform a first partial task on a first data-based data slice of the sub-set of data-based data slices. When a second DST execution unit has a processing speed that is a threshold speed greater than a processing speed of the first DST execution unit, the method continues with the DS processing module identifying at least one encoded block of the first data-based data slice for transferring processing responsibilities to the second DST execution unit.