Please note:
First things first, this is just an accumulation of several members fixes/workarounds including one or two of my own. I am not claiming to be the one who discovered all of them. Just trying to consolidate the info in one place.
Tips/Suggestions/Observations:
1. If you have 2 HDDs, I have found moving the systems Page File to it's own drive (2-5GB partition.) separate from the OS seems to lead to smoother play.
How to move the page file on:
http://support.microsoft.com/kb/307886
http://maximumpcguides.com/windows-vista/move-and-optimize-windows-vistas-paging-file/
2. Download and use the http://www.fallout3nexus.com/downloads/file.php?id=3808. (READ THE IMPORTANT NOTES!!)
3. If saves appear to freeze while loading, do not interrupt it. (Ctrl+Alt+Del) It can take up to 5 minutes when the game decides to be finicky.
Actually, if you do Ctrl+Alt+Del, and task manager pops up, I'm quite confident if you just close it down again, and let the game alone it will load eventually. This happens on both my rigs. If Ctrl+Alt+Del doesn't pull up the task manager, there is a good chance it is truly frozen, but not always. (After 5 minutes it's very likely.)
4. The Gamebryo engine has always been picky about some background apps running while playing. It's suggested to run a clean boot. http://support.microsoft.com/kb/331796 This will stop most programs from running in the background utilizing resource, freeing them up for the game engine. AV software should be disable, if not this way, at least manually while playing.
You are aiming for 150-200ish MB for XP, and 800-1000ish MB for Vista. Those are good target numbers, but just get it as low as possible.
5. Make sure you have the latest http://www.microsoft.com/downloads/details.aspx?familyid=D5692CE4-ADAD-4000-ABFE-64628A267EF0&displaylang=en and http://www.microsoft.com/downloads/details.aspx?FamilyID=333325FD-AE52-4E35-B531-508D977D32A6&displaylang=en installed and is working properly. Some people have had it installed, but reinstalling it over itself solved issues for them.
Issues/Solutions:
Issue 1: My DLC downloads kept stopping with a "The server does not support http....."
Solution: Don't open anything while it's downloading, just walk away til it's done. (I noticed every time I opened a browser to go online, or Windows Explorer..(To pass the time.)..anything, it would interrupt the download and give me that error.) This is apparently an HTTP issue, but I can seem to download anything else without issue, and I can download a poop load of stuff without issue. Just not with GFWL.
Issue 2: The runtime error on exit.
Solution:
First make sure you have a good install of http://www.microsoft.com/downloads/details.aspx?familyid=D5692CE4-ADAD-4000-ABFE-64628A267EF0&displaylang=en and http://www.microsoft.com/downloads/details.aspx?FamilyID=333325FD-AE52-4E35-B531-508D977D32A6&displaylang=en
If that fails:
Disable GFWL (DLC needs to be moved to offline mode if you have them.)
Disable: I have found the simplest way to disable GFWL is to rename the GFWLive.exe to GFWLive.exe.bak. This way when/if new DLC comes out it's as simple as removing the .bac from the name to get GFWL back up. (I've had issues with other methods.)
Default install: C:\Program Files\Microsoft Games for Windows - LIVE\Client\GFWLive.exe
Moving DLC to offline mode: (Not officially supported, but it works fine.)
First you must make Hidden files and folders viewable.
XP:
http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/tips/hiddenfiles.mspx
Vista:
http://www.bleepingcomputer.com/tutorials/tutorial130.html
Windows 7(RC):
Now navigate to:
XP:
C:\Documents and Settings\[YOUR USER NAME HERE]\Local Settings\Application Data\Microsoft\Xlive\DLC\425307d6\00000002
Vista:
C:\Users\[YOUR USER NAME HERE]\AppData\Local\Microsoft\XLive\DLC\425307d6\00000002
There will be 1-3 folders inside. (Depending on what you have.) These are the DLC folders.
OA and The Pitt:
Open each folder and move the DLC files (3/DLC) from each Content folder to the Data folder in the Fallout 3 directory. (6 files total.) If you Copy/Paste them, make sure to delete the originals, or rename the DLC folder. Otherwise you will have 2 entries for each DLC.
Broken Steel:
BS is a little different, as there are a few bik files that also need to be moved. Follow the same instructions as above, but then copy the 5 bik files to the Data\Videos directory.
Then enable them using http://www.fallout3nexus.com/downloads/file.php?id=640 The Data Options in the Launcher will not work correctly without GFWL.
Issue 3 and 4: CTD upon entering the Pitt - Missing DLC radio signals.
Solution:
Apply offline mode as described in Issue 2.
Disable the TP (Or other DLCs depending on the issue.) with http://www.fallout3nexus.com/downloads/file.php?id=640.
Load last save.
Save right away. Quit game.
Re-enable the Pitt/OA with FOMM, start game, load last save. (Continue is fine.)
Issue 5: Ammo press bug
Solution: Download http://www.fallout3nexus.com/downloads/file.php?id=5586.
Issue 6: Crashing (Codecs)
Solution:
You can try manually searching for the bad codec with http://www.softpedia.com/get/Multimedia/Video/Codec-Packs-Video-Codecs/InstalledCodec.shtml. (XP & Vista.)
XP:
Try using http://www.codecguide.com/download_kl.htm or http://www.cccp-project.net/. Note: You will have to add Fallout 3 to the ffdshows "do not use with" list in the config utility for K-Lite. (Found through the Start>All Programs>K-Lite method.)
Or
You could make a system restore point, and use http://nightmare2013.brashendeavors.net/.
Keep in mind this is going to make some things not work properly. It will set XP back to default codecs. (The system restore point is to undo it.) At worst, you may have to reinstall some things.
If the game works now, you need to weed out the codec that is the issue. (Install each program one at a time, then test.)
You can always just restore your system to the previous state, so don't worry.
Now, if you do use it, when it asks SP1 or SP2, just select SP2. I have used it with SP3 several times and there are no issues.
Vista:
Use http://www.free-codecs.com/download/vista_codec_package.htm
Issue 7: Crashing (2+ core CPU)
Solution: Try adding this line to the [General] section of the Fallout.ini.
iNumHWThreads=2
And change the 0 to 1 for this line
bUseThreadedAI=0
Issue 8: Patch 1.4 put me back to level 1
Solution: Use http://timeslip.chorrol.com/fomm.html to move the Fallout3.esm back to the top of the list.
Issue 9: Crashing/Freezing (Windows 7 + Nvidia card)
Solution: Try http://www.gamesas.com/bgsforums/index.php?showtopic=980768&hl=nvidia.
Issue 10: Hitching/Stutter
Solution:
1. Try deleting your Temp files.
2. Use InstalledCodecs (Link above in Issue 6) Look for ArcSoft 3GP Splitter, ArcSoft Audio Decoder HD and ArcSoft 3GP Splitter. All three of them are DirectShow Filters. Disable them.
Issue 11: VATS lag (Workaround)
Solution: Download and install http://camstudio.org/. And be sure to get the Camstudio Lossless codec to. (To install it, decompress the zip folder, then rightclick the camcodec.inf file and select install.)
Now go into the region section, and select Fixed Region. Put 1's in all 4 boxes then select OK.
Now under options, tick 'do not record audio' then select Video options.
Choose the CS lossless codec for compressor.
Put Quality to 1 with the slider. Then for the Max Frames slider, leave to the far left.
Before playing Fallout 3, run Camstudio and start it recording. When you are done, stop recording, and just Cancel out of the 'save file' part.
This had no noticeable impact on game play on my rig, but removes the VATS pause.
Issue 12: Crashes (Misc)
Solution:
1. If you have an Asus Xonar soundcard, you need to turn OFF the GX function in the Xonar Audio Center.
2. Try removing ASUS gamerOSD and/or smartDOC
3. Restore default control scheme.
4. Try reinstalling the latest http://www.microsoft.com/downloads/details.aspx?FamilyId=2DA43D38-DB71-4C1B-BC6A-9B6652CD92A3&displaylang=en
Issue 13: DVD does not see disk. (Workaround. Needs 2 PCs on a network.)
Solution:
The work around is to install it on a PC that can see it. Run the FalloutLauncher.exe so the game creates the 3 ini files needed. (Guess at what you think it will run at on your rig, and select that. Low-Ultra button, and set the desired resolution.) Now, share that DVD drive over the network.
You will have to add the http://www.home-network-help.com/share-file.html.
Then install Fallout 3 through the network to your rig.
Copy the 3 ini files in My Documents\My Games\Fallout3 folder to the new installs My Documents\My Games\Fallout3 folder.
Run the game from the Fallout3.exe not the FalloutLauncher.exe.. (Avoids disk check.)
You can manual edit the ini files to adjust the settings, or rerun the first install and copy the new settings over again.
Issue 14: Crashes (VATS/On saving. After updating from 1.4 to 1.5)
Solution: A full uninstall/reinstall of both GFWL and Fallout 3. Let GFWL do the updating from 1.0.
Issue 15: Can't move once BS has initiated and you are in the hospital bed.
Solution: Open the console (~ key) type showracemenu and chose one of vanilla races.
If you used a mod to age, or change your character after creation this can happen.
Good luck.