I thing Fallout 4 demands a DirectX 11(+) GPU to operate as intented.
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Multi-GPU graphics boards do not share memory banks, they are treated as discrete engines and are allocated individual resources for their operations as SLI clusters do !!!
Also a dual GPU works like an SLI internally. So each processor from your GTX 295 has only 896MB to operate with.
Meaning automatically you are below min. specs.
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But there is a trick to get the game running on DirectX 10 graphics cards, but with a low framerate thus unplayable. For those who want to try it, here's how :
1. Download and install Windows SDK for Windows 8 : http://msdn.microsoft.com/en-us/windows/desktop/hh852363.aspx ( this will also work for Windows 7 )
2. After the SDK installation go to your Windows System32 folder ( C:\Windows\System32 ), find and run dxcpl.exe
3. In the "Scope" section of the window, click on the "Edit List..." button and enter the location of your Fallout 4 executable ( Fallout4.exe ), then press the "Add" button and the "Ok" button
4. In the "Device Settings" section of the window, set the "Feature level limit" to "11_0" and be sure to check "Force WARP"
5. Press Apply/OK and there you have it. You can now start the game, but will probably not be able to play it because of the ultra-low framerate!
Other Information:
1. You can install Windows SDK for Windows 8 without .NET Framework 4.5. If you have .NET Framework 4.0 that will do just fine.
2. I've let all the main features to install.
3. This method will work if you fulfill most of the minimum requirements, except for the graphic card one (DX11 compatible gpu).
Also i do not know if it works on W10. !!!