If you add the same delay for the same input there's no statistical way to remove the noise because at that point it's no longer noise -- it's bias. That said,

If you add the same delay for the same input there's no statistical way to remove the noise because at that point it's no longer noise -- it's bias. That said, it's fairly easy to tell if a CPU spends time sleeping or doing actual work, so it depends on who is in control of the CPU.