the exact same task on the same hardware that doesn’t use disk or network can still take different amounts of times, a very good example of this is the execution time of code challenges, i submitted the same code to leetcode like 20 times for the same problem, and sometimes it took more than 500ms (faster than 2% of solutions) and once it took 288ms (faster than 98% of solutions), even though NOTHING changed in the environment, input or actual code that ran!