Replacing fan solved the High-Frequency Buzz problem of Penryn MBP

[novocaine]

My new Penryn MBP had the very annoying high frequency buzz. It's definitely not the noise from the fan and it's quite "stable" and always there even the machine is idling. The buzz is not really loud but in a quiet room it's quite annoying. And if you put your ear close to the speaker on one side (in my case it was the right side), you can clearly hear the buzz even in a noisy room. I went to the apple store on campus and they thought it could be from a faulty fan and thus ordered the part and replaced it for me. Now the machine is super quiet! So if you MBP also has this kind of high frequency buzz, it's not something normal. Get the fan replaced!