Why does my CPU downclock and stutter during intense arena combat in The First Berserker: Khazan?

My CPU downclocked mid-fight, causing a frustrating stutter. I tried adding case fans, but it only dropped temps by 2℃. I used GamePP Hardware Sensor Page to monitor VRM heat, then adjusted VCCSA from 1.25V to 1.20V in BIOS. Cinebench R23 confirmed VRM temps stabilized at 75-80℃, with fan speeds at 1400-1600RPM per HWiNFO64 and case temps at 72-76℃ per GamePP.