Problem with seams in displacement maps

I added a rather nice displacement to the terrain in my map, and it seems to work fine, but with one glaring issue: there are visible seams/cracks in the terrain that follow the camera and the player. Enabling precision UVs and crack-free displacement doesn’t get rid of them. Turning off adaptive displacement does, but then the framerate is severely bogged down, even on my monster PC. I want to know if there’s a good solution that can get rid of the cracks without affecting performance.