do i have to have an extra install of rome total war?

[caeser44]

do i have to have an etra install of rome total war, will it improve performance?

[Tellos Athenaios]

You mean the back up of your original RTW folder? If so, then:
No it won't improve any performance, and
No you don't actually need it,
but...

As long as you keep playing EB or Vanilla, if you start playing other mods using the same executable you may find that these mods now don't work anymore since EB has overwritten certain files. For example you want to play a mod with custom made vegetation (like EB has, but a different kind), you may find yourself still ending up with EB vegetation (and not the other mod's vegetation) - and vice versa. It's just that EB may still interferre with other mods, and therefore if you want to play other mods it's highly recommended to have a different RTW install for such purposes.