Why does my CPU downclock during intense combat in Monster Hunter Wilds?

The sudden stutter during Ancient Dragon hunts was a pain. I tried adding fan airflow, but temps only dropped 2℃. I used GamePP Hardware Sensor Page to lower VCCSA from 1.25V to 1.20V in BIOS. After stabilizing, VRM temp dropped from 85-90℃ to 75-80℃ per Cinebench R23. Memory temp is 58-63℃. The settings are locked.