It's not too loud, when the PC side panel is closed I can barely hear it. It makes this weird high-pitched rumbling noise, I don't really know how to describe it. I've found a video on YouTube with the same problem. The user who uploaded this video isn't actually me.
It isn't exactly as loud as in the video and my performance doesn't change when the sound occurs, I can still play Skyrim fine, the GPU only makes this sound when I'm playing games like Skyrim or BF3. When I'm derping around the internet it doesn't make this noise, when I turn on my PC it doesn't make the noise either. Anyways, I'm going to take my GPU out of my motherboard and clean it with a air pressure compressor.
interesting, I think it still could be worn bearings resulting in a noisy fan, it is not uncommon. Also I know some motherboards have a fan on their south-bridge heatsink and sometimes its located flush with the pcie slot. Can you check to see if you have this type of setup and if so make sure there is nothing touching your SB HSF.