Civilization IV is slowing down as the game progresses.

If you are experiencing sub-par performance with Civ, try the following suggestions:

• Go to www.windowsupdate.com and apply updates
  
• Update graphics and sound drivers
  
• Close other background applications
  
• Stay away from Large and Huge maps since they require additional ram
  
• Turn graphics and texture settings to low quality in the options screen
  
• Turn off Antialiasing
  
• Try both windowed mode and fullscreen (1024x768)

In-game movies are playing too slowly.

If you are still experiencing stuttering or slow movie playback after the 1.61 patch, try the following:

• Open the config (ini) file in notepad, and find the line which reads HideMovieBackground = 0, set it to HideMovieBackground = 1
  
• The intro and victory movies expand to fill the screen, so play the game at lower resolutions (like 1024x768) to get the best performance.
  
• If that doesn't help, a set of lower resolution movies is available for download here.

Out of Memory Error

If you are getting a video memory allocation warning, you should try reducing the graphics level (in the options menu) to low. If it still occurs and you want to ignore the warning, find this value in the config (ini) file, HideOutOfVRamWarning, and set HideOutOfVRamWarning = 1 using notepad.