Why does my CPU temp skyrocket and clock speeds tank when my city expands in Frostpunk 2?

Once my population hit 5,000, the CPU load just went nuclear, and the Cooler Master B240's smart scheduling was completely out of its league. I watched my core temps bounce violently between 88-94℃, which sent my clock speeds diving from 5.2GHz down to a pathetic 3.1GHz, making the game feel like a slideshow. At first, I tried cranking the fan curves to 'Aggressive' in the motherboard software, but while the noise was deafening, the temps stayed glued to 90℃—a total waste of time. I eventually dove into the BIOS and forced the AIO pump header to Full Speed, while dropping the radiator fan trigger threshold to 45℃. Checking HWiNFO, the coolant temp slowly dipped from 38-42℃ down to 32-35℃, and the cores finally settled between 76-81℃. I actually hit two Blue Screens of Death trying to undervolt at first, but things stabilized once I backed the offset off from -0.1V to -0.05V. Now there is a constant low-frequency hum from the pump, but the performance is finally uncapped. Benchmarks show the temp curve is flat now, with frame times sitting steady at 5.1-6.4ms.