Why do textures look like pixels while riding in Ghost of Tsushima?

Galloping across Tsushima in 4K, I noticed distant mountains loading in chunks like pixels, which felt fatal to the experience. I tried lowering texture quality in-game, but the visuals became blurry and I only gained five frames, which felt like a meaningless compromise. I opened the GamePP Resource Scheduler and set the game and storage driver priority to Realtime. Frame generation time converged to 7-11ms per RTSS, memory load dropped to 62-74% per CPU-Z, and fans hit 1600 RPM via SpeedFan.