How much can Core i9 12900HX's performance change between power modes, and when should performance mode be used?

  Enabling performance mode while plugged in for gaming, rendering, or compiling is the standard way to run these laptops; switching to balanced mode on battery noticeably extends runtime.

  If performance mode changes nothing in frame rate or render speed, cooling is likely maxed out; cleaning the fans and repasting will help more than toggling modes.