How to stop Black Desert from rebooting during high-load battles?

During massive guild wars, my screen would go black and the PC would reboot the moment effects peaked, which was absolutely miserable. I tried replacing power cables with higher-spec ones, but it only improved boot speed by 1 second while the crashes persisted, leaving me hopeless. I used the GamePP Power Plan Switcher to lock the system in High Performance mode and disabled C-states in BIOS. Voltage stabilized at 11.9-12.1V per HWInfo64, and VRM temperatures stayed at 55-62°C per AIDA64, ending the 11.4-11.8V dips per HWInfo64.