This save is inside a world-generated Dwarven Fortress, as an adventurer. No mods, unless you count the Phoebus tileset.

The problem is that every time I move, it takes literal minutes for the lag to end. I can fast-travel out just fine, but if I drop out of fast-travel while underground, any non-free action(sheathing weapons, checking inventory, ect.) brings about minutes of lag. Not sure why, hoping someone who knows what they're doing can use this to figure it out.