Internal. The noise just sounds like my case fans are ramped up, but its definitely coming from the hard drive because if I power the system up without it unplugged the sound stopped. Also turning off the fans in my system doesn't do anything.
Its just stopped doing it after quitting out of a game, really odd, has been loud for days. Hard drive temperature came back from 0C to 27C like it should read.
Any reason this could be happening? Not that big a deal but still.