Here we go again again. The OnePlus 5 was caught cheating on benchmarks in order to achieve its chart-topping performance.
A detailed investigation by XDA-Developers discovered the mechanism of the cheat. Hit the source link for the full details, heres the TL;DR version.
When a benchmark is detected, the 5 locks the little cluster of its Snapdragon 835 chipset at its highest possible clockspeed 1.9GHz. This isnt an overclock, but it does disable thermal throttling. The big cluster is not affected by this.
Thats enough to push the multi-core benchmark results as high as they are, single-core results are unchanged (still, most people just look at the multi-core result). With cheating disabled, the little cluster spent only a quarter of the time at max frequency, so this also makes performance more consistent.
Interestingly, in CPU-only benchmarks like Geekbench, the OnePlus 5 didnt heat up that much faster. Its when GPU benchmarks are run that the heat becomes too much the back of the phone was 50 C! Note that GPU clocks arent changed, but keeping the little cluster at max speed is enough to push thermals over the limit.
Not all benchmarks are affected, heres the list of benchmarks that OnePlus checks for. Note that the secret build listed in the chart has a different package name, so it isnt detected.
The official statement from OnePlus claims that this way it shows the performance potential of the 5.
PS. The OnePlus 3 cheat was of a similar nature, though not identical. There the minimum frequencies of both the big and the little clusters were raised. There was still some thermal throttling going on, just to a smaller degree.