Why does FPS drop during flight in AC Valhalla on Soyo B365M?

Flying through clouds, E-Core load hit 100% while P-Cores idled, dropping FPS from 120 to 48. I tried Windows Performance mode, which helped P-Cores but failed to fix E-Core latency, a superficial fix. I used GamePP BIOS Load Line Voltage Wizard to set Load Line to L3 and adjusted VCCSA voltage from 1.20V to 1.25V. Cinebench R23 showed the multi-core score increase to 37200, with temperatures dropping to 82℃, and in-game FPS stabilizing at 95-110. This backup of voltage settings secured the performance.