It's also required that you have New Vegas running in windowed mode, if you don't want to crash upon alt-tabbing with EnableUnsafeMemoryHacks=true. Vanilla Skyrim used over 1GB of VRAM, but it should be less with vanilla New Vegas.
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. I've set them to use my card's 2048 MB of VRAM if you have more than that, set it higher. In your driver program, ensure that your New Vegas profile has Anisotropic Filtering and Anti-Aliasing Mode set to Use Application Settings. I'll keep this as no-bullshit-y as possible.
