It appears that Fallout 4 is only using 1 of the 2 GPUs on my HD 5970. Is there anyway I can get the game to utilize both GPUs?
Well, you are lucky mate !
It so happens that i own 2 HD5970 adapters.
I'll start with the good news.
You can force AFR-Friendly through Catalyst Control Center -> Gaming -> 3d application settings (click on 'add' and choose the game's executable 'Fallout4.exe') You will know what to do from here.
Now, the bad news...
The game does not have a native crossfirex profile from AMD that also scales well.
Forcing afr-friendly enables crossfirex, but with many issues.
Try it and don't despair too much.
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