Celeb Glow
news | April 30, 2026

Fallout 3 Freezing

Can anyone tell me why Fallout 3 GOTY edition keeps freezing after playing a certain time? Already updated the video card driver. Windows updated. Using Windows XP. Display card is ATI HDI48XX series. Already in windowed mode, no vertical sync, chose medium graphic details.

Thanks.

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3 Answers

There seems to be a problem with multi core processors and a suggested fix can be found here. Although it states to be for Win7 I heard it work for other windows versions as well.

The game engine has some issues with processors that have more than 2 cores. You can force the game to only use two of them and it will stop the freezing. I haven't had it freeze once since I did this several days ago.
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.

Not sure if it's gonna solve your problem, but you might want to give it a try as it's simple to test out (and to reverse the changes if it's not helping).

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For non-Steam versions of the game, make sure you have it patched to the latest version, which you can get here

If that doesn't work, I highly recommend this Tweak guide it helped me when I couldn't get it to work on 8.1 but it will work for other OS's. The biggest problem the game has is the multi core one but it might also help to open the .ini file and enable the hard drive cache.

Also (believe it or not) the sound in the game can crash it try to double the sound cache if your system can handle it.

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In case someone comes across this more recently, this is a well known problem and the primary fix including other performance remedies can be found in this Gopher video:

Modding Fallout 3 - Part 4 : Performance & Stability (BASIC)

However, in my experience if you want a 100% stable game you use the Tail of Two Wastelands mod to import Fallout 3 into the New Vegas engine and mod it for stability. There are simply more things you can do including using NVAC - New Vegas Anti Crash.

Currently have put ~143 hours into a play though and I might have had one or two crashes? Regardless I can't remember the last time I did have a CTD. The only problem I have ran into is after about 6 or 7 hours the game gets slower and starts to chug in which case you just restart it.