sorry for the double post but I wanted to add an update on my problems and resolution with fallout 3.
I was encountering crashs, stuttering and sound problems on a freshly installed vista x64 ultimate system, the specs are as follows:
Fallout 3 patched 1.7
All settings max 4AA 10AF
Windows x64 ultimate
i7 920 overclocked to 4GHZ
gigabyte x56 UD5 motherboard
Sparkle GTX 260 216 OC
x-fi fatality pci soundcard
6 gig ddr3 @ 1200mhz
now to begin with I had a problem with the radio music stuttering badly, this is with all the latest sound drivers, I fixed this by installing creative alchemy and adding fallout 3 via reg path with "HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Bethesda Softworks\Fallout3\Installed Path" and setting:
Buffers: 6
Duration: 5
Voice Count 128
This restored 7.1 sound and cured the radio music (sounds perfect now)
For crashs and stuttering I have the latest nvidia forceware installed (190.62) manage 3d settings\global settings I changed:
Multi-display/mixed-GPUacceleration to: single display performance mode
Vertical sync: Force on
Threaded optimisation: on
in the fallout.ini I changed to:
bUseThreadedAI=1
and added:
iNumHWThreads=2
this allows fallout to only use 2 cores
Finally I made fallout3.exe run in xp sp2 compatibility mode
my game now runs stable for hours with the only stutters to load objects and textures when in the wastes, interiors run smooth without any hitch, just to remind you I am running on a fresh Os install so no problems with codecs and such, if you really cannot get the game installed or run fallout atall it is worth trying this if your really want to play and own a similar setup to mine.
All of these tweaks where found through searching other boards and google, most of you probably already tried these but I thought id post this to help anyone who was not aware.