I've already checked, and Fallout 4 does not have any SLI bits. If anyone wants to try (since I don't have my copy yet, and won't play until it's ready to go), you should use nVidia Inspector and use the Skyrim SLI bits into the Fallout 4 SLI profile: 0x42C80005 (Elder Scrolls V: Skyrim). I've also heard that the Fallout 3/New Vegas SLI work as well: 0x42800005 (Fallout - New Vegas, Fallout 3)
Paste that into the SLI compatibility bits section. (There's two of them, paste them on both fields.) Don't forget to go to the "NVIDIA predefined number of GPUs to use on SLI rendering" section and set it to SLI_PREDEFINED_GPU_COUNT_FOUR, then the SLI mode to SLI_PREDEFINED_MODE_FORCE_AFR2. Do that for both fields.
EDIT: Don't forget to unlock the Frame Rate. Looks like it was locked on launch:
[url]
http://steamcommunity.com/sharedfiles/f ... 1447077828[/url]