Ok, ran into this problem big time fighting a nightmare army in Scythia. It was almost entirely archers and horse archers and dealt me a narrow loss. The problem was the flaming arrows. I had seen things slow to a crawl for a few seconds before with a few volleys of flaming arrows, but it tended to recover when they stopped. This time it got really, really bad and slowed to about 1 frame per second or maybe half that. It did not recover when the fire arrows stopped so the whole battle sucked big time.

Fire arrows should be disabled. I found the following info on how to do disable the fire, but have not yet tried it:

fix by commenting out the lines:

file:
descr_arrow_trail_effects_new.txt

lines:

effect_set 2 3 4 > fiery_arrow_set
{
lod 1000
{
; fiery_arrow_smoke
}
}

effect_set fiery_arrow_set
{
lod 1000
{
; fiery_arrow
}
}
----------


My understanding is that you don't have to comment out the smoke, just the "fiery_arrow" line, and that will cure it.