Some Video Cards have very loud fans.
I have 7800GS from BFG installed in 775Dual-VSTA, and the fan was absolutely, unbearably loud. Even when just browsing in Vista RC1, it sounded like a hair dryer.
I removed the fan with the casing and put a regular 80mm fan on the otherwise massive copper heatsink with a "makeshift" bracket. No aftermarket HSF would fit the BFG hole pattern.
Have been using it since November 2006 with no issues at all.
That's why I decided to go with EVGA for my 7950GT instead of BFG. I believe that it was kinda negligent on BFG side to put such a loud fan on a card, relatively expensive in April 2006 (~$300). Their support was completely oblivious to my questions regarding the aftermarket solutions, they just told me "I don't know what would fit".
They lost a customer to EVGA.