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  • Open up the fallout.ini file in: My Documents\My Games\Fallout3
  • Find the line:
 bUseThreadedAI=0 
  • change it to:
 bUseThreadedAI=1 
  • Add another line after it and insert:
 iNumHWThreads=2 
  • This will limit the game to 2 cores and prevent the engine bug from causing the game to freeze.
  • If the game still crashes try
iNumHWThreads=1