I vaguely remember the old memory running out problem.
1) I think you need to stop the auto save feature.
2) Keep at least 3 saved games and save over them in rotation
3) keep Task manager open along with another medium sized program in the background. If the game runs out of memory, sometimes you can recover after closing that secondary program.
Edit: Galciv sometimes doesn't know how to free up memory properly.... by running a second program in the background, you prevent stupid Galciv using up ALL your available memory, so you keep some memory in reserve and use it to recover when the game does run out of memory.