Hi, Im planning on putting my old 20gb hard drive into a portable external hard drive case. Then connection that to my computer using the usb connection. It will be an add on to my internal hard drive. I want to store all my music files on the 20gb external hardrive(usb). I am wondering since the 20gb will be connected through the usb and not internally will it be slower? Also would playing my songs and accesing them from that drive be slower than storing them in my internal drive?