I just noticed after running my AC and having my driver'* side window down (restaurant drive-through) I noticed that I'm having a rattling sound coming from under the hood. i turned the AC off to hear it better because the fan was on high, and the rattling went away. I turned the AC back on, and the sound returned. My question is if this can be expected of a compressor, or if it could be a sign of it going bad. Last summer I noted having an extreme loss of engine power with the AC on. It was almost unbearable how slow the car was with the AC on. I'm not noticing the same severe loss of power, but now the rattle is present from the compressor. Do you think it'* anything to worry about?

Most likely it'* either the air gap in the clutch plate or the bearings starting to go in the compressor.

Unless..the added load of the compressor being driven on that belt is causing another accessory or pulley to make noise

Custom, Like Bill said, it could be the air gap on the a/c clutch, or compressor itself loading down too much. Try turning the compressor by hand maybe to feel how much mechanical resistance, then compare to the Bonnevilles. Just a thought.