you put it with the game exe(you do know were that is do you?) is this the mod then read the page Place the exe in your Fallout New Vegas game folder and run it - You may need to run the patcher in admin mode - It will patch the game and make a backup of the original executabl Fallout: New Vegas 4GB Patch.

Why use this tool, when there are 4GB patch tools and PE Editors you might ask? Well the Steam envelope for the FalloutNV.exe does not tolerate any tampering and will error out if you modify it that way, so this tool was created by MonochromeWench to get around. This is useful when using lots of Mods and Texture Packs. 3,650,902 FNV4GB is a tool to load Fallout New Vegas with the Large Address Aware executable flag set so the entire 4GB Virtual Memory Address Space can be used by the game.