I don't believe that there are any mods that affect the AI's strategies in a battle, so you will just have to stick through it. I know it is fun to get three units of spartans to face endless peasants, but you gotta sacrifice some fun if you get frustrated easily by lag. You could also drastically drop your graphics settings suring the battle and just reset them at a later battle, but I am not sure that will work. The best solution I have found is to simply pan the camera over and study the battle by looking at your numbers. I am sorry to add that my home computer, which has even higher specs than the one you listed (8gb ram, i7 4 core 8 thread processor), also lags on chokepoints. Is there any way to force the AI to not stack units together and actually stay in formation somewhat? If not, any other ideas? Once the units are grouped together and the game is not paused (on 1x game speed), it doesn't matter if the units are in the view area or not, it still lags. If I do manage to pause it, however, the lag stops and it goes back up to about 25-30 fps, even if the enemies are grouped together. After the AI groups their units together, it goes down to less than 1 fps and the game becomes completely unplayable, I can hardly even move the mouse enough to pause or exit the game. When the battle first starts, and before the units group together, I average about 20 fps while both armies (around 10,000 troops total) are fully in the view screen. When I am defending choke points with my army (bridges, gates, etc.), and the enemy army reaches the choke point, the AI group together ALL of their units (I usually have 5,000 soldiers on each side) into the area that one unit would normally occupy, and this causes HUGE lag. I am experiencing MASSIVE lag when I am playing certain maps against the AI in RTW.

Rome total war lag