Troubles with moving movieclips


I´m making a christmas card for Crew9 of Hyper Island. I´ve done it so it works, but it uses far too much of the cpu, for now almost 90%. Now the movieclips are moved by an onClipEvent (enterFrame)-code, but it´s not good enough. Is there any other way to do it so it doesn´t clog the CPU?

link to fla:

and the swf can be seen at:

Thanks in advance for help!