This game will still get maf errors regardless of operating system because the game is 32-bit, so it still has memory limits.
To avoid maf errors set affinity to 1 processor only so it won't get interference from other tasks. Plus the game plays faster as well.
Make sure to run the processor editor, but it should already have the patch in 64-bit windows by default. but double check to be sure.
to set affinity:
1. Start game and minimize it (alt+tab out or maybe alt+enter)
2. start the task manager (right click the task bar and select," Start Task Manager", or press ctrl+alt+del and select, "Start Task Manager"
3.select Processes tab
4. right click CivilizationIV.exe (or whatever it's called) and select, "Set Affinity..."
5. uncheck all CPUs except 1 (doesn't matter which one)
This will reserve 1 cpu to the game only and nothing else. It should make it faster and lessen the maf error (but not eliminate it)
Good luck
-=Mark=-