i got it working now for me

for users who have solutions with "NVIDIA DRIVER CRASH AFTER 5-15MINUTES GAME CRASHES EVERYTIME" and it works even with SLI

the solution is:
i have got 2x680ies from gainward phantom, wich are slightly oced factory, identical cards at first sight BUT they are not identical as well.
diffrent ascis means diffrent quality means card 1. got 1137mhz core 2. got 1167mhz max core

the boost core nvidiainspector says is @1150mhz wich means card 2. is over that and clocks down to 1150 well! but not card 1 its maximum clock is @ 1137mhz.
to fix the problems with driver crashing you can do 2 diffrent things

OVERCLOCK the smaller mhz core card so that both cards can match the core clock (1150mhz boost in my case)
or
DOWNCLOCK the stronger one (to 1137mhz in my case)

so they dont get out of sync evertyime and game crashes

do this via nvidiainspector it works well

http://fs5.directupload.net/images/151112/oo4p4ny3.jpg

to enable sli simply put in nvidia system activate ALTERNATE FORCE RENDERING 2 for fallout4.exe and falloutlauncher.exe

i hope it helps let me know in my opinion it helped

EDIT: for users how are running only one video card it could help to down or overclock to match its boost, nvidiainspector shows you this like in the pic i posted

Good job figuring this one out, I have only one GTX 680 so no SLI, and I'm afraid this will not help me.. This is what I get in my NVIDIA inspector, as I'm not allowed to post links,

Current clock 849 NHz, Memory 0 MHz, EST max 1202 MHz

GPU Clock 1137 MHz, memory 3004 MHz, boost 1202 Mhz

Default clock is the same as above..

Any ideas? Honestly I'm running out of options

hm 1137 seems a often readed clock core

try to downclock to 1137mhz maybe this works

let me know

I'm running two Asus GTX970's
According to NVIDIA Inspector

GPU 0
Current clock Est Max 1316 MHz
GPU clock Boost 1253 MHz

GPU 1
Current clock Est Max 1329 MHz
GPU clock Boost 1253 MHz

If I adjust the Base Clock offset to bring the est max for both cards to 1316 MHz, then the GPU clock boost changes as well, so I'd end up with

GPU 0
Current clock Est Max 1316 MHz
GPU clock Boost 1253 MHz

GPU 1
Current clock Est Max 1316 MHz
GPU clock Boost 1240 MHz

In other words both of my GPU's are showing the same GPU clock and boost speeds, but different est Max speeds. If I adjust the slider to make est max the same then the clock and bost will be different. Both cards were purchased at the same time from the same vendor.

It works bro!! Thank you so much for helping me, been playing non-stop since you helped me !

you are welcome figuring this out 10hours a day and did everything but nothing really helped me unless this

i think to much "boost" on geforce 6xx systems cause fallout 4 to crash

everyone who reads this reduce core clock speed about 30-50mhz and try again

I've got to say thanks, I'm using a single 680 also and this seems to work (I'm in the middle of by far my longest session - and I've had about 50 to 60 5-10 min sessions). I followed what I believe Ed0r described to Ceco.

I'll keep playing and hope I haven't spoken too soon, but more people need to try this: lower the boost clock to whatever the default base clock is - hope I've got that right!

Bump, this really worked. Not had a single crash since doing this - great game when you get the chance to really immerse yourself without worrying about it crashing all the time.

I'm not sure exactly how the nvidia inspector works for overclocking, as I usually use the EVGA precision program. I have a GTX 660, and I'm not positive on how to downclock and am too concerned to play around with it when I dont know how to use the program. Can yo help me?

I am getting

Current clock 324 MHz, Memory:324 MHz, and Est. Max 1149 MHz

GPU clock 1044 MHz, Memory: 3004 MHz and Boost:1110 MHz

Defualt clock 1072 MHz Memory 3004 MHz and Boost:1137MHz

If you could help me I'd greatly appreciate it!

I have a 680 too and it crashes after random amount of time. We need more confirms of this work around and someone need to report to both Bethesda and Nvidia. Its not right that you need do clockspeeds to make it work. BUT very nice find on the workaround if it works!

I'm not comfortable with downclocking or overclocking..

I'd have to say placebo affect as there's no SLI support so the game has zero idea there's even a 2nd card running.

Unless there's a huge sample of people saying a drop in core speed works I'm thinking cooinsidence.

For sure, not true. Both of my GPU's get up to around 85-90% usage, using the AF2 setting.

with dx11 sli bits forced to BATMAN ARKHAM CITY and disabling afr2 your fps would be better i found this out to myself

Unless Nvidia and Bethesda have released the SLI profile for Fallout 4 there is no multi card support...

Just ran the game again. GPU1 = 91% usage, GPU2 = 91% usage.