Sounds like a connector (onboard) or a bad fan, Possible RMA?
Originally Posted by Mikecdm
Use earplugs? Honestly this is a common occurrence with these cards. My 260 makes the same squealing sound under load and if you search, there are a few threads about the same thing.
Some people suggest RMA'ng the card and hoping that the new one doesn't make noise, but it's very common. The only other thing to do is to live with the sound or don't use the card.
I haven't folded with mine for a while, but in a few days it's going to start making music to my ears.