It is working fine in X3:Albion Prelude but in Fallout New Vegas, my side screens flicker when I load the game (both in game and at the main game menu).

I am using 3 monitors (20" at 1200x1600, 30" at 2560x1600, and 20" at 1200x1600) and using 2 AMD Radeon 6970 cards in Crossfire. I am using the latest version of SoftTH and have both the d3d9.dll and config.SoftTHconfig files in my main Steamapps>Common>FalloutNewVegas folder. In the Falloutprefs.ini in My Games>fallout, I have made these changes: iSize W=4960 iSize H=1600.

The problem is that both side monitors flicker when I load the game. This hasn't happened in another game I've been using SoftTH with (X3 Albion Prelude).

Can anyone offer any advice? Thanks.

Here are my config file settings:
[main]
renderResolution=4960x1600
nonlocalFormat=RGB32
keepComposition=0
smoothing=1
debugD3D=0
zClear=0
vsync=1
tripleBuffer=1
screenshotFormat=jpg
dllPathD3D9=auto
dllPathDXGI=auto
dllPathD3D11=auto

[overrides]
forceResolution=0
antialiasing=0
processAffinity=0
FOVForceHorizontal=1
FOVForceVertical=1

[head_primary]
sourceRect=1200,0,2560,1600
screenMode=2560x1600

[head_1]
devID=1
sourceRect=0,0,1200,1600
transportResolution=1200x1600
transportMethod=nonlocal
noSync=0
fpsLimit=0

[head_2]
devID=2
sourceRect=3760,0,1200,1600
transportResolution=1200x1600
transportMethod=nonlocal
noSync=0
fpsLimit=0

Not sure if I can offer any help but perhaps check the Refresh rate??
I see nothing wrong with your Config. Not sure why it would flash like you stated it does?? Perhaps it dont like the Crossfire mabey try disabling one GPU..

I would advise posting this on the SofTH Forums. you could also look through the many posts there.. I used to use SofTH Before I got my Matrox TH2Go thingie and found many fixes on the forums by browsing them for other games FOV fixes mostly..