wondering about download speed
 

I am wondering I have cable internet ( 1Mb download &256 upload.) I adjust the speeds and all, I notice one min i can get say 60 kb download on a song, but only say 10 on a movie. I also notice that even if say i dont have limewire downloading anything my connection is still loaded with files going and comming. even if no one is downloading anything. any thoughts would be great. thanks