Fatal Graphics error - workarounds?

Quintus Sertorius mentioned in other threads that "fatal graphics error" is caused by memory issues - however, during my Romani campaign I get most of those (and the only ones that wouldn't go away by multiple reload attempts) while trying to enter a battle against Carthaginians. I've got around 6GB of free RAM memory and lowest graphics settings, no difference between fullscreen and windowed modes. No log is being generated after modifyng ebii.cfg as instructed.

It doesn't matter how much RAM you have, M2TW is hardcoded to only use up to 2GB.