First off PC Specs:

i7 4770k @ 4.2GHz

EVGA GeForce GTX 980 SC (Hybrid Water Cooling)

16GB DDR3 RAM

256GB Samsung Evo Pro SSD

1TB Mechanical Western Digital 7500 RPM

Zowie FK1 Mouse 400 DPI

Corsair K70 RGD Keyboard

After I installed Fallout 4 for the first time the game automatically recommended Ultra settings for everything so i left it at that and launched the game. Immediately upon entering the game I notice that there's horrible input lag on my mouse, I mean coming close to 1 second of input lag. The first thing I tried was disabling V-Sync in the .ini file which did nothing. It is also worth noting that this issue persists when in Character Creation and when you finally get into the game, so it's not isolated to a menu issue.

List below of things tried:

• Turning off V-Sync (iPresentInterval=0) - Did not fix
• Turning all Graphics down to LOW, all shadows off etc. - Did not fix
• Selective Start-up, turned off everything that wasn't essential to normal operation. (Discord, Chrome etc) - Did not fix
• Changing PhysX from Automatic to CPu / GPU - Did not fix
• Changing Resolution - Might have Fixed
• Changing setting in NVidia Control Pannel (Max Pre-Rendered Frames, Pref Refreshrate, Power management, V-Sync) etc - Might have Fixed

Okay so somewhere during the NVidia Control Panel changes and the Game Resolution change the issue got fixed. List below of changes made before it fixed:

Launcher Settings

• Changed Resolution in launcher to 1600 x 900

Nvidia Settings:

• Maximum pre-rendered Frames - 1
• Power Management Mode - Pref Maximum Performance
• Preferred Refresh Rate - Highest Available
• Vertical Sync - On

NOTE: I went back and changed the resolution to 1920 x 1080 and also went back through each option I changed in Nvidia Control Panel back to it's default Global value without being able to re-create the input lag. Please also note that iPresentInterval is still set to ZERO meaning V-sync is OFF in game. (iPresentInterval=0)