Why does Space Marine 2 lag during Tyranid swarm fights?

I felt pure desperation when Tyranid charges triggered violent frame drops, totally killing my immersion in melee combat. I tried enabling Extreme Performance mode, but while idle clocks rose, the throttling persisted. I then used the GamePP Fan Curve Configuration Panel to lock system fans at 100% speed once they hit 70℃. After this, frame times converged to 12-15ms per RTSS, and VRM temperatures stayed stable at 78-84℃ per HWMonitor, ending the 4.2GHz to 2.8GHz drops seen in AIDA64. It's a total lifesaver.