I've noticed a huge frame rate drops while fighting with mounted enemies in Siege of Paris DLS.
Is not noticeable while fighting with only one, but when 2 horsman or 3 charging you at the same time - then frame drops apears.
As more enemies do this at the same time at the same time, the greater the problem became.
Cannot record video to proof of right now, but i will try in the future.
If anyone notice same problem - report here please.