Xbox 360 Slim loud and dirty?

Hi, I have a Xbox 360 slim that I bough about a week ago. So, I have a few questions. Is it a bit loud when running a game like Modern Warfare 2? Because its sorta loud, but not as loud as the old 360. Second question is that my xbox 360 slim has like grease marks at the side. I have it standing up. Theres like greasy fingerprints at the side and I want to know how to clean it. Please answer both of my questions. Thanks!!