No, the performance does not drop if I stand still, though it DOES drop for the whole session if I move, and especially much if I switch between interiors and the overworld. I measured my FPS standing still after loading a save in Forsaken Fortress (31 FPS), standing still in forsaken fortress right after getting the sword (facing the door, 29 FPS), and I measured it again when I got to Dragon Roost island, at which point I was experiencing 27 FPS. While moving, right after loading the save, I'd only drop to around 29 FPS, around the time of getting the sword I dropped to 25 FPS, and on dragon roost I dropped to 20 and lower while moving.
This is after changing all of my graphics settings back to what I remember the defaults to be, in D3D.
This is after changing all of my graphics settings back to what I remember the defaults to be, in D3D.