Frame jitter and VRAM spike in battle scenes, is the Power Plan mode exceeding limits?

VRAM usage spiked to 98% with 11-38ms frame time jitter per RTSS. I tried manual fan curves but stutter persisted. GamePP Power Plan Switcher locked High Performance, stabilizing frequency. HWiNFO showed 68-72℃ temps, VRAM at 82-85%, and smooth dungeon runs without downclocking.