Due to an issue with the game, loading times drastically increase with the number of CPU cores which especially affect black loading screens with the green Vault-Tec logo in the bottom right corner (can often last up to a minute), even with the best M.2 NVMe SSDs available today.

There are 2 possible workarounds:

1) Using Alt + Tab during loading screens, then reopening the game once music stops playing in the background after a few seconds.

This is the most straightforward method which works properly with all configurations, but returning to the game before music stops playing causes resolution issues which can only be resolved by restarting the game.

For this method to work, VSync must be disabled (in "\Documents\My Games\Fallout4\Fallout4.ini", set "iPresentInterval=0" under "[Display]" to disable it), as well as Windowed mode and Borderless in the launcher. Disabling VSync requires limiting FPS to 60 in NVIDIA Control Panel (3D Settings > Manage 3D Settings > Program Settings > fallout4.exe > Max Frame Rate = 60 FPS) or AMD equivalent.

2) Making the game use fewer CPU cores (Task Manager > Details > Fallout4.exe > Set affinity) which may affect stability and performance depending on CPU model. The official requirement is a minimum of 4 cores, but the game seems to work normally with only 2 cores and loading is instant without the need for Alt + Tab at all.

As for how the first method works:

While the game is out of focus during a loading screen, FPS is temporarily unlocked and loading resumes in the background. For some reason, loading times in Fallout 4 are tied to FPS (strangely, only the black loading screens are significantly affected) and as a result, this method allows the game to load as fast as it possibly can instead of being limited to loading at only 60 FPS. That being said, permanently unlocking FPS by simply disabling VSync is not a viable option due to FPS higher than 60 resulting in various and usually major issues with the game's engine.

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