I have a new macbook 2.4ghz and 4 gb ram....just got the itch and I have the usb buffer set all the way to the left as i go with my ssl. However when I am active on the vci meaning when I scratch I notice that I start to get a lot of crackling and distortion on the song. When its not set all the way I notice it has lag whats the best setting. What should I do will it help to get the power adapter?