No confusion is intended. Just saying from experience in this field how are these devices setup and tested. Everyone tends to forget how Windows OS, Android OS and etc need some sort of system file and registry cleaning. I would test this way first just to make sure all system are running at their peak performance.
As for CPU, NPU, MPU, GPU sure they're rated speed not much you can do except OC (over clock them but not worth it today) Test results should be just prep before performing them.
As you know test results can vary and that's why in a lab or Model Office (this is use to test out software, hardware) I've been involved in these type of testing. Another one is UAT (user acceptance testing) where they come in test the installation of software and hardware so it will be what is expected to run as. Like a final check before anything is release into companies or corp environments.