https://www.theregister.co.uk/2018/09/05/huawei_on_smartphone_benchmarks/

Huawei has addressed the issue of tweaking a phone's performance to improve its benchmark scores, after being caught redhanded.

The practice isn't new, and has been carried out by a number of phone makers in the past. It works like this: To boost a system's benchmark score, the phone detects whether a popular benchmark is running and ramps up the clock frequency.