How do I stop checksum errors and frame drops in ancient ruins?

While navigating ancient ruins, the frame rate would suddenly drop from 90 to 40, causing me to miss critical clues. I tried lowering the frequency to 6000MHz in BIOS; it was stable, but the minimum FPS dropped from 55 to 42. I used the GamePP Memory Controller Load Monitor to lock voltage at 1.4V per HWInfo and adjusted tRAS. MemTest86 errors dropped to 0, and memory latency stabilized at 65-70ns per GamePP Sensor, with temps at 52-58℃ per AIDA64.