If you were able to determine that your CPU was getting "weak or fragile," what would you do about it? You'd replace the logic board, which is exactly what you'd do if the CPU suddenly stopped functioning altogether. As long as your CPU is functioning normally as far as you can tell, there is nothing else to be done, and no point in knowing anything more about your CPU than Apple Hardware Test can tell you. You can obsess over this if you want to, but it will do you no good and will be a waste of your time and energy.