This issue is very annoying. I have 2BG of total memory, and ~1.6Gb free when opening the game. (Windows XP 32.) Currently playing on huge earth-like map (in the 1900s), and yes after a couple of hours the system runs out of memory, the turns slow down to almost a full minute (i am guessing it runs out of ram and start using the hard drives), and if I don't restart the game it will eventually crash. I guess this will be my first and last huge/large map... Shame.