Hi,
I am the author of this Isandlwana battle video I made a year ago with Orient mod for Napoleon Total War: 1800 british vs 19200 zulu.
https://www.youtube.com/watch?v=17ECsVIMrwE
Video made with Alienware 17 R3, i7-6700HQ, 16 GB RAM DDR4, Nvidia GTX 970M 3 GB DDR5. It's true I had lag because of the amount of units but I could play the battle with graphics settings at max. In Empire Total War I am having trouble with 5000 men per side, I have almost the same lag, sometimes even the game stops and depending on the mod even crash to desktop. I find Empire Total War far more unstable than Napoleon Total War and Shogun 2 Total War, have you experienced the same? What is your opinion?
PS. Yes, I am obsessed with this topic.