other than logic bricks, are there any other source of game lags in the BGE?
like too much scenes, high poly meshes, high reso images etc…
my game lags big time, but only in a certain time… couldnt figure out the cause 
Almost anything can help make your game lag.
To much physics, high detail texture, high detail models.
and anything else
turn on ‘Show Framerate and Profile’ on the game menu, that will tell what is eating your frames.
oh cool thanks mrhippieguy ^^