Why is Elden Ring loading slow with G.Skill Trident Z Royal DDR5 6800 due to northbridge overheating?

Loading levels took forever due to black screens. I tried lowering graphics, but the lag persisted. I changed the northbridge fan curve to linear 1800 RPM in GamePP. Northbridge temp stabilized at 65-70℃. PCIe bandwidth recovered to 8GT/s per CrystalDiskMark. The loading is now fast and reliable.