Numbers can still be noisy. For example, the measured time per frame might
be a true computation time of this frame, plus a random amount of time (noise)
that CPU/GPU spends on some unrelated work. Hence, the metric fluctuates.
Nevertheless, there’s no ambiguity of what the number means. And, there are
also rigorous theory and testing tools to handle such noise. For example, you
could take multiple measurements to estimate the distribution of a random
variable, or you could take the average of many measurements to eliminate the
noise by the law of large numbers.

3. Performance is comparable and convertible