Windows 7 - Fallout 3 on Windows 7 w/quad core

Vista SP2 with a dual core worked fine. After upgrading to a quad core and Windows 7, I was lucky if I could play more than 5 minutes without a freeze.

A fine gentleman named Nicholas Head posted this solution on his blog. Along with several others, I can confirm this fix works! (YRMV)

Fallout 3: Video/Display Freezes, sound keeps going

by Nicholas Head 7. February 2009 00:35

Ever since Bethesda came out with the 1.1 patch for Fallout 3, I couldn’t play the game anymore. Once I got into the game and started wandering around, I’d randomly “freeze” up… the video would stop updating, but the sounds/music would still play. Keyboard clicks and mouse clicks did nothing, requiring me to ctrl+alt+del and kill the task manually.
It looked like I was SOL until the next patch, but I found some help online:

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.

Surprisingly, this worked like I charm. I do indeed have a quad core processor, so it sounds like this was the culprit. Why 1.1 broke the game for me.. I have no idea. It sounds like Bethesda needs to do some better testing on multi-core processors.


Hopefully this helps someone else out there!

I've never really encountered that problem tbh. And Fallout 3 is up to patch 1.7, so the issue may have been resolved by now.

It hasn't been resolved on 1.7! Still there.

I am so glad I found this forum! I have a quad core, am having the same freezing problem... Its been driving me crazy!! I will try this fix and see if this fixes it.

Edit: I've been playing for over 3 hours now with NO freezes! It was freezing every 2-5 mins at least!

major thanks for this!!

Sadly, this did not work for me, running 1.7 update

Then again, my copy was crashing out to the desktop on load, not during gameplay, so I'm not sure if its the same issue.

I can't even start the game. I get a black screen for about 15 seconds followed by a error message. It does Oblivian the same way.

Fixed my time to time crashing copying those lines to my Fallout3.ini. I'm playing on 1.7 update and full graphics.


For me it did that same thing on other games when i had installed Nvidia 191.07 WHQL drivers.

Try Nvidia 190.62 WHQL drivers. Fixed that kind of problems for me.

I'll try that. When I try to update game I get a patch error saying "invalid patch file". Thank you for helping me with this. I'm not real bright with this stuff. When my buddy sent me this OS I had to upgrade my hardware so it would take and I thought that might have something to do with the problems I'm having. After purchacing the mobo the chart showed that my 7900GT was not compatible but all my EA games play without a hitch.

You need to know do you play US or UK version of the game..
both patches can be found here: Fallout: Welcome to the Official Site
download both versions and try witch one works for you.. I had UK..

Haven't had a single problem with Fallout 3 on Windows 7 with my Phenom X4 9950, with any of the nVidia drivers.