Mechanisms are provided for performing approximate run-ahead computations. A first group of compute engines is selected to execute full computations on a full set of input data. A second group of compute engines is selected to execute computations on a sampled subset of the input data. A third group of compute engines is selected to compute a difference in computation results between first computation results generated by the first group of compute engines and second computation results generated by the second group of compute engines. The second group of compute engines is reconfigured based on the difference generated by the third group of compute engines.