I have the same model iMac as you and yes my Superdrive is noisy too. You can actually feel it reading a disc if you put your hand on the surface it's sitting on. It doesn't really annoy me, I just like to think of it as a DVD-R drive that everyone wants and that I have. That usually helps . Besides, if you've ever used some discs in a PC before and heard that PC's drive rev (not to mention the loudness of the fan in most PCs) you'll be glad you own your iMac. I know I am
All new CD/DVD players/burners I've tried are noisy when a disc is inserted. I find it annoying, as I can't have a disc mounted without having that multi-frequency aircraft-engine-like sound boring holes through my head.