Before I say anything: This is not like the other threads about this issue because my issue happens even without the power adapter plugged into my laptop. I have a 2010 15" MBP that I have been using with my exact same setup for years with no problems. Yesterday morning I woke up and the only thing I did differently was swap out my RAM to my new replacement RAM that just came back from RMA. After that, (and after a lot of troubleshooting to narrow it down), it seems that any time I have my external speakers or headphones plugged in and I have my ethernet cable connected, I'm getting a lot of buzzing noises. It seems to also happen when I connect my external monitor but it's much more amplified with the ethernet. Get this: I went to my router and took a roll of wrapped ethernet, plugged one end into the router and I merely touched the roll of ethernet up against the metal casing of the MBP and the buzzing could be heard through the headphones. Plugging the ethernet cord in just made it that much louder. I'm pretty convinced this has something to do with a lack of shielding in the MBP. I don't know why it became more evident now than it ever was before. Swapping the RAM back did not solve the probem. I'm not sure if I could have done something to mess with the shielding but I've opened my casing tons of times before with no adverse effects. Does anyone have any ideas?