An embodiment of the invention provides an apparatus for computation of processor clock frequency ratios in a multi-processor system. The apparatus includes a computation engine configured to determine a processor clock frequency ratio by reading counter values of a first counter and of a second counter within a frequency ratio computation interval, and configured to determine a value of the second counter at an end of a frequency ratio valid interval where the frequency ratio is applied, wherein the frequency ratio valid interval is subsequent to the frequency ratio computation interval, and wherein the frequency ratio valid interval does not overlap the frequency ratio computation interval.