Some mobile phones optimise for certain popular benchmarks for example by overclocking during testing. Thus if you rerun the test over and over you would get a

Some mobile phones optimise for certain popular benchmarks for example by overclocking during testing. Thus if you rerun the test over and over you would get a different result due to thermal throttling. In application space, as far as I know the best way to test is to compare real work loads over prolonged periods of time. Getting real test data can be hard but not impossible for example recording alpha/beta users using the app.