Just dance on intel core i3 problem

[AdeDarma]

i just want to play just dance on my laptop on dolphin 3.5 with Intel Core i3-2350M @2.3GHz with 6gb ram and the problem is the song is seems like laggy but the movements and gameplay is fine (even littelbit lag sometimes).
why this is happened? because i have a slow machine or i should configure something in the setting or what?
Please help