Are you replacing/removing the original battle_interface.dll completely from the Modules folder before putting the patched one in? The game loads everything in that folder with the extension .dll, and it can load duplicates. If the old one is still in there, then the game will try to use both patched and unpatched simultaneously. That'd make the game slow.
What resolution do you run the game at? I'm not sure how ENB affects the choices, but if a lower resolution can be tried it might help.
Another possibility is I assumed there was only one game version released. But, perhaps your game is somehow different. If you check the Engine.exe application properties, does it say in there "File Version 1.0.0.1 Copyright 2002 Akella ENGINE Language Russian" and the file size is 1,187,903 bytes.
What resolution do you run the game at? I'm not sure how ENB affects the choices, but if a lower resolution can be tried it might help.
Another possibility is I assumed there was only one game version released. But, perhaps your game is somehow different. If you check the Engine.exe application properties, does it say in there "File Version 1.0.0.1 Copyright 2002 Akella ENGINE Language Russian" and the file size is 1,187,903 bytes.