Instructions
Load "Civilization 4." Wait for the main game menu to appear.
Click "Options" in the main menu.
Click the tab labeled "Graphics" in the Options panel.
Set "Anti-Aliasing MultiSamples" to 0 (zero) in the left pane.
Adjust settings in the left pane to a lower level as needed. Settings for "Graphics Level," "Render Quality Level" and "Globe Quality" are available. The possible settings are Low, Medium and High.
Select the following options in the right pane by clicking in the check box:
"No Combat Zoom"
"Effects Disabled"
"Globe View Buildings Disabled"
"Low Resolution Textures"
Click "Exit."
Restart "Civilization 4" for the graphics changes to take effect.