It does not require so much power. But it strains the hardware in a way, that the power consumption of the hardware becomes very spiky. And Nvidia's Ampere GPUs are another reason for it. They can also create huge power consumption spikes. Nvidia relaxed it with the RTX 4000 series. If the PSU is old then the capacitors in it can only store a fraction of their original energy capacity. And if there is a big energy consumption spike then they run out of energy very quickly and then the voltage goes down. And yes, FF14 is very odd in this case. But it is also a very good stability test.



Cheers