In my experience that crazy mouse speed is only when moving camera around (mouse right click), so reducing DPI will not help. With crazy speed I mean, when you move mouse like 2mm and it moves camera by 180 degree.
Use l2encoder/decoder to edit user.ini and change value for these settings: MouseX=CameraYaw Speed=+3600.0
MouseY=CameraPitch Speed=+3600.0to lower, for example 500 I had this problem when played l2 interlude on virtual machine and helped when changed both to 150.
Hello. I play on mac osx and it runs pretty smooth. I use wine v1.7.33, with lower version I get errors. Also I have installed a lot of stuff from winetricks (http://askubuntu.com/questions/316025/how-to-install-and-configure-wine)