I'm currently working on troubleshooting this one for me.... Titan X and 3930k. Both on custom water and OC'd the snot out of. Something I have noticed so far is at some points outside, the GPU and CPU utilization drops no almost nothing and the frame rate is a constant to 9 fps. Simply turning 90 degrees to the side and boom, GPU maxes out and up to 90+ FPS. 1440p ultra settings here. Did no changes to the settings or any ini... Simply started the game, auto-detected settings and boom, stutters. Some people mentioned turning god rays to medium, but that had no effect. I did test with the lowest possible settings and it did fix it, so my hunch is one of the graphical settings is giving it issues.