Fault Tolerance (FT) has become a major concern in computing systems. Instruction duplication has been proposed to verify application execution at run time. Two techniques, instruction memoization and precomputation, have been shown to improve the performance and fault coverage of duplication. This work shows that the combination of these two techniques is much more powerful than either one in isolation. In addition to performance, it improves the long-lasting transient and permanent fault coverage upon the memoization scheme.