Why does MGS Delta stutter during combat on my Manli Star RTX 5080 OC?

Combat in Metal Gear Solid Delta: Snake Eater was janky with my Manli Star Interstellar RTX 5080 OC. Frame time jumped from 8ms to 15ms. I tried DLSS Balanced, but it blurred the image. I then used GamePP Hardware Sensor Page to increase VRAM frequency from 13Gbps to 14Gbps and set render resolution to 100%. RivaTuner confirms stable 8ms frame times. Combat is fluid now.