Z-Floor Patcher
This patcher is based on the xEdit scripts located found on the Nexus here: https://www.nexusmods.com/skyrimspecialedition/mods/66652
RobertGK and Kojack found that there are potential issues when objects are located outside of the bounds of the worldspace. Moving objects horizontally will place objects in neighboring cells, but items or navmeshes with a z-coordinate < -30,000 can cause issues with the game engine and cause stuttering. This patcher cycles through all placed objects and all navmeshes. If it encounters anything with a z-coordinate less than -30,000, then it is placed at exactly -30,000.
Currently this patcher is based on a pre-release version of Synthesis/Mutagen. Make sure you are using the latest Synthesis version and set this patcher's preferences to "Match"