My Ultra 9 285K clock speeds are jumping all over the place during heavy combat in The First Descendant. How do I stop the lag?

The frame times were bouncing between 12ms and 45ms, and that kind of inconsistency is a disaster during intense Boss fights. The P-cores on my Ultra 9 285K were hitting 88-92℃ under load, triggering an aggressive downclocking mechanism. I tried enabling 'Ultimate Performance' mode in Windows, but the CPU temps just spiraled out of control, and my FPS actually tanked from 110 down to 85. It became clear that a simple power plan wasn't going to fix a deep scheduling issue. I dove into the BIOS, locked PL1 and PL2 power limits to 253W, and nudged the ring bus frequency to 4.2GHz. Checking RTSS, the frame time variance shrank from 33ms down to a tight 4-7ms, making the controls feel incredibly responsive. I actually crashed the game a few times trying a risky -0.05V undervolt, but once I backed it off to -0.05V, it stayed rock steady. Core temps now hover around 76-82℃ with fans at 2100-2400 RPM. AIDA64 stability tests confirm the scheduling is finally sorted, and the system glitch is gone.