For our temperature testing, we measure steady-state GPU temperatures under load. A reading under load comes from running A Plague Tale: Requiem for 30 minutes.
The Performance BIOS has a clear advantage for thermal performance, too, given the GPU hit just 47C in my testing, with the hot spot at 66C. The Quiet BIOS runs warmer, but is still well within safe limits given the hot spot hit 80.1C.