Lineage II System Requirements
800 MHz Pentium III CPU
384mb RAM
GeForce 2 graphics card
8 GB hard disk space
These to my knowledge are the very lowest you can go where the game will still "function" however they highly recommend a better system.
Also from Lineage's main page;
Quote:
If your system does not meet the minimum requirements:
The game either will not run or will not function properly. In order to play the game without any problems, we suggest that users meet the recommended specifications.
If your system only meets the minimum requirements:
Set the graphics options of the game to the lowest levels to maintain smooth game play. Click the Lower Detail check box in the Game Options to set this option.
* Lineage II requires DirectX 9.0c or above. Windows® 95, 98 and NT are not supported. Install DirectX 9.0c or above and the latest drivers for your video card.
If someone else has additional information and who knows more about the topic would be wonderful to hear from you. This to my knowledge however is all I know and that usually system specs on the minimal can't be pushed to much withouth sacrificing quality so much it's not worth it.