Go to the
Fallout New Vegas folder and open enbseries.ini in a text editor, like Notepad++, and set the first line to UseEffect=false. Save and close.
Open enblocal.ini in a text editor, like Notepad++, and edit the following lines:
[MEMORY]
ExpandSystemMemoryX64=false
ReduceSystemMemoryUsage=true
DisableDriverMemoryManager=false
DisablePreloadToVRAM=false
EnableUnsafeMemoryHacks=false <-- As a last resort, setting this to 'true' may actually benefit some people getting stutter otherwise. Beware that it could potentially cause CTDs on some systems.
ReservedMemorySizeMb= <-- Possible values include 128, 256, or 512. It may require some tweaking depending on system hardware, but 256 is a good starting point.
VideoMemorySizeMb= <-- Go
here to get the vramsizetest tool. Run the vramsizedx9.exe. Note the number it reports back. For Windows 7/XP, subtract 170 from the reported number to get your final value. For Windows 8.1/10, subtract 350 from the reported number to get your final value. The final value is what you want to enter here.
EnableCompression=true <-- Weaker systems may benefit from this setting being false.
AutodetectVideoMemorySize=false <-- Set the VRAM manually.