A few years ago, Samsung, HTC and a few other companies were caught manipulating performance of their smartphones to score high in various benchmark apps including GeekBench and Antutu Benchmark.
According to latest reports from XDA, OnePlus and Meizu is targeting specific applications like AnTuTu and Geekbench to boost the clock speeds of the chipsets inside the OnePlus 3T and Meizu Pro 6 to score high.
“OnePlus was makings it CPU governor more aggressive, resulting in a practical artificial clock speed floor in Geekbench that wasn’t there in the hidden Geekbench build. It wasn’t based on the CPU workload, but rather on the app’s package name, which the hidden build could fool.”
However, OnePlus has promised that they will remove these tweaks in a future update.
“In order to give users a better user experience in resource intensive apps and games, especially graphically intensive ones, we implemented certain mechanisms in the community and Nougat builds to trigger the processor to run more aggressively. The trigger process for benchmarking apps will not be present in upcoming OxygenOS builds on the OnePlus 3 and OnePlus 3T.
XDA have included multi-core throttling results and graphs to elaborate "How manufacturer discovered doing this". You can check them Here.