Antar Bolaeisk

Probably the fan is on the way out but honestly that post didn't make much sense even on the fifth re-read. What do you mean by when the case is off? do you mean that you've taken off a sidepanel or something? If that is the case, pun not intended, that removing bits of your case reduces the noise you should be looking for anything that rattles. Just get your head in there with your ear up close to everything, don't be afraid to apply pressure to panels on the case to see if that reduces the noise.

How hot is the card getting? You should be able to check this in the nVidia control center or if not then try a program called GPU-Z. Has your case got adequate ventilation? Have you anything else overclocked? If so then return everything to stock and work your way from there. Not sure on the power requirements for the card but maybe someone else could drop by and tell you if that is enough though I'd imagine it would be.