Frostpunk 2 is hitting Vcore instability with my RT620P during city expansion. Do I need to lock voltage?

While expanding my city in the freezing cold, my frames suddenly tanked from 100 down to 35. It actually made me want to see how far I could push my VRMs. I found that with the RT620P, the auto-voltage was bouncing between 1.1V and 1.3V during load shifts, causing the clock speed to crater. I tried 'Ultimate Performance' mode in Windows, but that just made the voltage swings even more erratic—totally naive of me. I headed into the BIOS advanced voltage settings and locked Vcore at 1.25V while setting PBO to Enhanced. The frequency monitor finally showed a stable 4.4-4.7GHz without the sawtooth pattern. At first, the CPU hit 93℃, which was scary, so I tweaked the fan curve and dialed the voltage back to 1.22V to find a balance. VRM temps are now sitting at 60-66℃ and the game is smooth as silk. Switched the motherboard profile to 'Extreme' and core temps are holding at 72-78℃.