I'll keep this as no-bullshit-y as possible.
In your driver program, ensure that your New Vegas profile has [b]Anisotropic Filtering[/b] and [b]Anti-Aliasing Mode[/b] set to [b]Use Application Settings[/b].
You can find enblocal.ini presets below. I've set them to use my card's 2048 MB of VRAM; if you have more than that, set it higher. In order to get the minimum VRAM required, load up your game and play for a wee while, and look at the amount of memory used under the ENB overlay's profiler section. Vanilla Skyrim used over 1GB of VRAM, but it should be less with vanilla New Vegas.
It's also required that you have New Vegas running in windowed mode, if you don't want to crash upon alt-tabbing with [b]EnableUnsafeMemoryHacks=true[/b]. And that setting is a game changer, as it greatly reduces stuttering if not completely eliminating it, when models and textures are being loaded (e.g, travelling across cells, transitioing from interior <-> exterior). So have New Vegas in windowed mode, and everyone's happy. Also, when a game is in windowed mode (Windows 7 and newer), the game gets triple buffering. This means you can have VSync enabled without the framerate juddering between 15 <-> 30 <-> 60fps.
I also recommend disabling the Steam Overlay for Fallout New Vegas. It causes issues when the interface pops up (e.g, recieving a message from another player) where many objects become fully transparent, and has caused issues for some users when [b]ExpandSystemMemoryX64=true[/b].
Explanation of settings:
If you want to use ENB's graphics modifications alongside the ENBoost part, set [b]UseENBoostWithoutGraphics=false[/b].
[b]EnableUnsafeMemoryHacks=true[/b] Brings two major benefits. And these are brought about as the game's models and textures are no longer mirrored into RAM (as is standard with Direct3D 9). Stuttering is exceptionally reduced, as is memory usage in the FalloutNV.exe process.
If you have texture mods installed, with the amount of memory being used exceeding your GPU's VRAM, Set [b]EnableUnsafeMemoryHacks=false[/b], [b]ReduceSystemMemoryUsage=true[/b], [b]AutodetectVideoMemorySize=true[/b]. We lose the benefit of reduced stuttering brought by EnableUnsafeMemoryHacks, but gain the benefit of the game no longer crashing or corrupting when the VRAM is not able to hold all of the game's models, textures, shaders, render targets, and frame buffers. This is done by ENB launching multiple ENBHost.exe processes, that are then filled with the game's models and textures.
If you have a card with a large amount of memory (e.g, 8GB), it's pretty much impossible for you to reach the limits of your VRAM, so you can just keep [b]EnableUnsafeMemoryHacks=true[/b] and have the best of both worlds.
Example enblocal.ini files:
ENB for best performance (no texture replacers, 2GB VRAM): https://pastebin.com/vhpRAFS0
ENB for game with texture mods & small GPU VRAM (size of all loaded resources > GPU VRAM size, ): https://pastebin.com/ix9G7wfg