So it might be that it just happened this once, but when sieging Rhemtoil Castle (Battania) using nothing ladders as siege engine the AI just stopped, significantly reducing my fps in the process.
This footage shows AI behaviour:
My fps goes (somewhat) back up when infantry is set to infantry siege ladders after the enemy AI pushes the ladders down. But as soon as it goes back to infanty is assautling walls my fps drops and the AI stops.
(Battle size: ~600 attacking Sturgians Vs. ~60 defending Battanians)
(We eventually won because the archers shot everyone down one by one that tried to push the ladders from the wall )
This footage shows AI behaviour:
My fps goes (somewhat) back up when infantry is set to infantry siege ladders after the enemy AI pushes the ladders down. But as soon as it goes back to infanty is assautling walls my fps drops and the AI stops.
(Battle size: ~600 attacking Sturgians Vs. ~60 defending Battanians)
(We eventually won because the archers shot everyone down one by one that tried to push the ladders from the wall )