A design and timing model for at least one circuit path of at least a portion of an IC design is loaded into a computer. At least one canonical clock variable associated with the model is defined; it includes at least one source of variation. The computer is used to perform an SSTA of the at least one circuit path, based on the design and timing model and the at least one canonical clock variable, to obtain slack canonical data. A clock period is projected, based on the slack canonical data, such that a cycle time canonical is projected to a different space than a logic canonical. Results of the SSTA and the projected clock period are output to determine performance compliance. Efficient operation of the computer is enhanced by analyzing a slack vector in a single timing run, loaded once, and multithreading timing propagation.