Potentially seeing through walls: a performance issue

[Acies]

I reconstructed one of the largest map in my mod. Imagine the frustration.
Sill, performance issues started to arise, even without objects placed...

Might it be related to textures?

You have a lot of imported textures/models? Have you made any custom textures yourself?

If they are in the same layout as the amnesia textures that could perhaps increase performance.