Future synchrotron radiation facilities such as the Advanced Photon Source to be constructed at Argonne National Laboratory will produce dedicated and powerful beams of x-ray radiation instrumental in advanced research in key areas of sciences, engineering, and medicine. The development of critical beamline optical components such as monochromators is pivotal in the successful utilization of the generated x-ray beam. The high heat load of the beam can severly distort, and thus adversely affect the performance of, such components. In this paper, a five-step numerical procedure to predict the performance of an x-ray monochromator subjected to high-power synchrotron radiation is described. The predicted performances of a model double-crystal monochromator system expressed in terms of its rocking curves satisfactorily presents the experimental results. This procedure can reliably be used in the design, evaluation, and optimization of monochromators and other optical components.