It is important to have a CLEAN INSTALL before doing any of the fixes below
Delete the game first, then delete these folders before a re-install:

• C:\Users\*username*\Documents\My Games\Fallout3
  
• C:\Users\*username*\AppData\Local\Fallout3

Make sure you also delete the remains of the game in your Steam folder before a re-install. Go to your Steam folder and then go to "steamapps" and then "common". If a "Fallout 3 goty" folder exists in there, delete it.

First of all, I would recommend you to run the game once, so that we have the .ini files (configuration files) all set-up.

When you launch the game from Steam, you'll see the Launcher pop-up. Go to Options and change your options to the ones that are on the image below (resolution depends on your monitor, of course):



After this, load the game until you get into the main menu and then you can exit the game.

I heavily recommend doing the patches/updates IN ORDER so that nothing goes wrong.

• Fallout Anniversary Patcher[www.nexusmods.com]
  What is this? Downgrades the game after the Anniversary Update for FOSE support and more. Makes the game 4GB aware and fixes the mod limit bug.
  
  How do I install this? Download the file and extract the files to where your "Fallout3.exe" is. Launch "Patcher.exe" and it will install. After it is done, press any key to close the prompt.
  
  
• Updated Unofficial Fallout 3 Patch[www.nexusmods.com]
  What is this? This is an unofficial patch with bunch of fixes.
  
  How do I install this? Download the file and extract its content. Then you will see a file with the ".fomod" extension. Change that to ".zip" (or .7z) by right clicking and renaming it. Then extract its contents to "Fallout 3 goty\Data".
  
  
• Fallout Script Extender (FOSE)[fose.silverlock.org]
  What is this? Even though this is not updated as of yet after the Anniversary Update and we won't be launching the game through it, it is still required.
  
  How do I install this? To open .7z files, you need 7zip, so make sure you have it or if you don't have it, download it here[www.7-zip.org]. After that, download FOSE and extract its content into where your game is installed (in this case Steam\steamapps\common\Fallout 3 goty)
  
  
• Command Extender[www.nexusmods.com]
  What is this? Required because of Updated Unofficial Fallout 3 Patch. Provides game patches to fix engine bugs.
  
  How do I install this? Put the "fose" folder inside of the zip file into "Fallout 3 goty\Data"
  
  
• Ogg Vorbis Libraries[www.nexusmods.com]
  What is this? Updated sound libraries that optimize the game's audio decoding, fixes an audio memory leak, sound related stuttering and boosts performance while reducing CPU strain.
  
  How do I install this? Extract the contents of the .zip into your Fallout 3 Steam directory, and replace the existing files when asked.
  
  
• New Vegas Anti-Crash (also works for Fallout 3)[www.nexusmods.com]
  What is this? This reduces game crashes.
  
  How do I install this? Download the zip and inside it you will see two folders called NVSE and fomod. Extract NVSE into Fallout 3 goty\Data folder first. Then go back into the zip, go into NVSE, and then Plugins, and extract "nvac.dll" into "Fallout 3 goty\Data\fose\plugins".
  
  
• Fallout 3 Tick Fix[www.nexusmods.com]
  What is this? Removes the lag from the game.
  
  How do I install this? Download the zip and put the fose folder inside "Fallout 3 goty\Data" folder.

Here, I will tell you some of the important config fixes. Make sure to do all of it.

• Field of View (FOV)
  Go to Documents\My Games\Fallout 3 and open FALLOUT.ini
  Under the [Display] section, find these two lines:
  fDefaultFOV=75.0000
  fDefault1stPersonFOV=55.0000
  
  Change these numbers to whatever you like. I would recommend between 90 and 100 for a 1080p monitor. Using a lower FOV for the second line is a better choice to avoid clipping since it is the FOV of the gun.
  
  
• Disabling Mouse Acceleration
  Open Documents\My Games\Fallout3\FALLOUT.ini
  Find the section: [Controls]
  Add the lines:
  fForegroundMouseAccelBase=0
  fForegroundMouseAccelTop=0
  fForegroundMouseBase=0
  fForegroundMouseMult=0

In this section, I will show you how to limit your FPS so that problems such as lip-sync and other physics related problems are gone.

For NVIDIA:

• Go to NVIDIA Control Panel.
  
• In the section on the left, go to “Manage 3D settings”.
  
• From that window, choose the “Program Settings” section.
  
• On the “Program Settings” section, choose "Fallout 3 (fallout3.exe)"
  
• If it doesn't exist, add it by clicking on "Add", go to "Browse", go to your Fallout 3 directory and select Fallout3.exe. Then click on Add Selected Program. Make sure it is also selected on "Program Settings" section afterwards.
  
• Find “Max Frame Rate”, change it from "Use Global Setting" to “On” and make it “100 FPS”.

For AMD, here's what Vaughners did:

To do framerate limiting on AMD, you can turn on a feature called "Chill" on a per-game basis in the driver software. I went to Gaming > Fallout 3 and turned on the switch for Chill, then set the framerate sliders to minimum 60 and maximum 100. That fixed the annoying lip-sync problem I had after going through all your steps (which worked amazingly, thank you!)

Why 100 FPS? Because 100 FPS is the maximum FPS that Fallout 3's engine can handle without physics breaking or lip-sync breaking. Though if you are having problems with it being on 100 FPS, you can go for 60 FPS as well.

After all this is over, launch the game through Steam! Have fun!

Fallout 3 page of PC Gaming Wiki[www.pcgamingwiki.com]was used during the preparation of this guide.