I am using eyefinity running at 5972x1080 (bezel compensated). I thought for sure last time I had fallout running, before I reformatted, that it autodetected my desktop resolution AND auto selected the proper aspect ratio for it (5.53:1)
Now it does not show my desktop resolution only a maximum of 1920x1080 and aspect of 16:9 (which is for 1 monitor only). Did something change? Or am I mistaken and it never worked?

I have it set up by modifying the .ini but the aspect ratio is still off and it is creating a massive stretchy fisheye effect. It did not do this before.

Also on this thread this guy states that he changes the aspect ratio and NOT the FOV of fallout.
http://hardforum.com/showthread.php?t=1468080&page=3
How is this possible? Does anyone know how to find this? I have searched through the .ini files and found no aspect ratio settings.

There are few games that auto detect dual monitors for actual game use, unless the game is actually programmed to take advantage of a second screen (IE: Supreme Commander) so I highly doubt you will get fallout to auto detect 3 screens for game use.

Thats not to say you can't get it to work though, as im sure you can, i just have no idea how.

I believe any game will run on multiple monitors if the monitor settings are set up correctly.

For instance, nVidia has several modes for dual monitor setups:
Single (only use on display)
Clone
Horisontal span (span horisontaly, the windows task bar spans multiple monitors)
Vertical span (...)
Dualview (Taskbar stays on the primary monitor)

If you have 3 monitors I bet the mode you want is ATI's equality of Horisontal span. This should span the windows taskbar accross all 3 monitors and also make games draw on all 3 monitors. I personally do not use this on my dual monitor setup because it creates several annoyances, ie. windows popup messages show up in the middle of the 2 screens. It is almost impossible to read without moving the messagebox to either monitor first. On a 3 monitor setup you won't have this problem, because the center of the desktop is in the center of the 2nd monitor.

*sigh* clearly no one read the post or has no clue what eyefinity is.

The monitors are linked together to form one large one via eyefinity software. They resolution in windows is set to 5972x1080. Games work just fine across all the monitors as it just thinks it is one large screen. Fallout IS working but the aspect ratio is wrong. It is pretty much taking the sides and stretching them completely out of proportion. I know that I had it set up before and it did not do this. Also if you check the link you can see how it is supposed to look and how he states he modified the aspect ratio fallout was using. That is what I want to know - how do I manually force an aspect ratio?

Edit the ini to use your resolution.

you want to look in the FalloutPrefs.ini for the lines:
iSize W=XXX
iSize H=XXX

Just change them to:
iSize W=5972
iSize H=1080

No you are not reading. It is ALREADY USING MY RESOLUTION. It is the aspect ratio that is the problem. Because the game is using the default 5:3 or 4:3 whatever, everything is stretched out to insane proporations on the side monitors. The thread states he modified the aspect ratio and not the FOV. Look at the two screenshots posted. The one that has game aspect ratio 16:10 is what it looks like. It SHOULD look like the one that has game aspect 48:10. This is what I am trying to achieve.

I don't know if you found the answer yet or not, but to fix this chanage the Field of View using the FDefaultFOV option in the falloutprefs.ini. Change it from 75 to 150. This fixed that problem on my multiheaded setup (5760x1080).

I do have a different problem though, the computers (including the one needed for the "gene projection" stage) don't fit, and are unusable.

I bought this again on PC because it is listed as an eyefinity supported game : http://support.amd.com/us/eyefinity/Pages/eyefinity-software.aspx - Very disappointed atm.
I changed the iSize to both 6028 x 1080 and 5670 x 1080 and it looks OK, but any option screens are almost unusable. I cannot find the fDefaultFOV file you refer to...

That's not the file. That's the setting you're looking for in the file named 'FalloutPerfs.ini' I believe.

That's what I meant. Not there for me. even created a setting called fDefaultFOV and set the value at 150 then 75 = No bueno. As long as I don't have a user-input screen open it's fine. It actually looks good, but those user input displays come up a lot.
There is no FDefaultFOV option in the falloutprefs.ini or the FALLOUT.ini - I created one and set it to 150 and no change.
Found a nice thread here :http://www.widescreengamingforum.com/forum/viewtopic.php?f=57&t=14785 that says to change the
iSafeZoneXWide=770
iSafeZoneYWide=15
iSafeZoneX=770
for a 5040 x 1050 display. probably what we are looking for. will have to play with the values for a 5670 x 1080.