I think it's due to NPCs getting stuck and try their hardest find a new path. C&C Generals has the same issue where AI spams commands. It's much worse in custom maps where AI doesn't know how to act, especially if there isn't any good pathfinding for the units.

Originally posted by Santax:

I have installed everything correctly and I have used it without any other mod, but the fps drop too much, it is almost unplayable, when I don't use it obviously this doesn't happen, has it happened to anyone else? I tend to play with many heavy mods at the same time and this has never happened to me

If you enable debug on the game and go into sandbox options, there is a debug tab for Knox Event Expanded. If you enable all of those debug print options and get a log where you reproduce this, I can have a look. These options will print if some operations are taking too long, so it might give a hint towards what is causing your game to drop so many frames.