Why does Final Fantasy XVI have wild FPS drops with Asgard DDR5?

I was so excited! When releasing skills on the grand battlefields of FF16, 64GB of RAM should have been effortless. I first tried manually locking the frequency to 5600MHz in the BIOS; while stable, the FPS ceiling dropped by 15 frames per RTSS, which was absolutely unacceptable. I enabled the GamePP Memory Controller Load Monitor to increase VDD voltage from 1.3V to 1.4V via HWiNFO64 and optimized the controller response latency. RTSS showed frame times converging to 13-17ms, and AIDA64 confirmed temperatures stable at 54-60℃.