If you're interested in playing Final Fantasy XI on your computer, but aren't sure if it can handle the game play, the following link will take you to the official benchmark created by PlayOnline for testing computers for compatibility with Final Fantasy XI.
Link: http://www.playonline.com/ff11us/download/media/benchmark01.html?pageID=media
Link: http://www.playonline.com/ff11us/download/media/benchmark01.html?pageID=media