Ok, I've spent roughly 20 hours over the last several months troubleshooting why I was getting random crashes. When I heard a new patch was coming out with stability improvements, I felt finally I can play without wondering when the next crash was going to pop up. Unfortunately the 1.3 patch did not improve anything for me. I had 3 crashes in 5 hours. The crashes I would get were always outside roaming the wasteland and never in the same spot twice. It never crashed indoors. The frequency of crashing increased dramatically when I had a companion with me. Crashes were also more frequent the farther into the game I got. My first play through was about 70 hours and I suffered through just shy of 30 crashes and did not use companions. A couple of occasions I played about 4 hours without a crash, and several times I would crash 4 times in an hour. I have pretty much done everything that has been posted out there. I even stress tested all the hardware on my computer to verify it wasn't the problem, tried different OSes, Tried different HDDs, despite other games playing perfectly fine, even oblivion.

My setup is a core2quad qx9750, 8gigs of ram, and a GTX480. This work around will only benefit quad core users. Essentially what I have done is eliminated the use of 2 cores of my CPU in Windows to get it to run as if it is a dual core. I have tried the "b_usethreaded AI" thing, which is supposed to do kind of the same thing to the game only, but like everything else it didn't improve anything. If anything it made it more unstable. After making the below changes, I have played 36 hours now without a single crash and 90% of those hours I had at least one companion with me. Hears the procedure:

1.Open MSCONFIG, you can do this by typing in msconfig under your start and search menu in windows 7 and vista
2.Click the boot tab
3.Click Advanced options
4.Check number of processors, select 2 in the drop down menu. Hit ok.
5.Reboot your pc, you will know it is working once windows is up by doing CTRL+ALT+DEL to check task manger. It will only show 2 processors instead of the normal 4.
6.Delete the INI files in your save folder to start a fresh copy in case it changes something based on number of cores on your processor. You will have to set up your video and game play settings again after doing this. (this step might not be necessary, but this is what I did)
7.To set your pc back to normal, follow the above steps, but instead, just uncheck the number of processors tab and reboot.

I suppose setting affinity would do the same thing, but I wanted a more permanent test before trying to do something like that. If you are getting crashes every few minutes, or the game won't launch, or crashing in the same location, this will probably not help you as you may have driver/codec problems. It should also be noted that I have had 2 loading freezes, which have never happened before, but no actual crash. I have read of numerous reports of loading freezes with the latest patch. I also have not had any performance hits doing this. The game runs just as good as it did before, didn't need to drop settings. That may vary for you depending on the speed of your processor.

Nope. Still crashes within 20 seconds of a new game or loading a save from the new game.

List of games that don't act like this:

Fallout 3
Fallout 1
Oblivion
Morrowind
Gothic 1, 2, and even 3
Metro 2033
Boiling Point: Road to Hell
The Witcher: Enhanced Edition
Fable: The Lost Chapters
Civilization 2, 4, and 5
All Total War games
Stalker: Call of Pripyat
Stalker: Shadow of Chernobyl
Sims 1, 2, and 3
Dragon Age: Origins
Mass Effect
Neverwinter Nights 1 and 2

17 items... May 17th was the date The Witcher 2: Assassins of Kings was released, another game that does not behave with near immediate crashes. Meanwhile you get another buggy 4 hour dlc.

Sorry it couldn't help, but the dual core fix will probably work for intermittent crashing. It sounds like if your game crashes after 20 seconds on load, there is another issue and your crash would not be random. I think it will help those that have a similar problem to what I described in the first post. Obviously this isn't then end all be all of crash fixes. It worked for me and I have read numerous others with a similar problem that it will probably work for. Also I haven't seen doing this posted anywhere, which is why I posted it.

Well, you can tell I'm bitter. I do remember reading somewhere that F:NV expects the default Windows codecs and hates any deviation. All options have not been eliminated and it's not the end of the world, literally.