Just like others, my game is laggy as long as there are too many NPCs on the battlefield, may it be in custom battle or in multiplayer commander battles.
I have AMD Phenom II X4 955 BE (4*3.2 Ghz), ATI RADEON HD 6870 (1.5 Gb Memory), and 4GB RAM.
The game become smoother (100 FPS) when there are fewer NPCs. However, at the beginning of a game I have between 20 and 30 FPS. I have tried even with the lowest graphics, it doesn't change anything.
I do not understand where does this come from since I have never had any problems with Warband or Fire and Sword with top graphics.
I know I'm not alone to cope with this problem.
Any idea ?