Most people will have lag in a very crowded area ex: like Bonfire at its busy hours. Usually the rate of how well your game(s) & certain other programs run is up to your computer's graphics card etc... You could try adjusting your video settings in game a bit to see if it can help with the lag a bit though. Go to the game's main menu click "options" then "video" and change the settings like so:
-Rendering Subsystem from OpenGL to Direct3D9
-Water Reflection Off
-View Distance to 0
-Also play the game in Window mode not full screen
Hope that helps some
(by the way in the future this kind of post goes in the "Game Help" section)