If your room is at 90 degree(i guess fahrenheits) and your gpu is at 80 degree(with same scale) then your temp sensor is broken.
i have a coolmaster 932 full tower and the computer is cooler then the room cause of the fans inside it.(this is the crossfire 6990s)
I don't know how familiar you are with the law of thermodynamics, but it's not possible to cool an object to sub-ambient temperatures using surrounding air, no matter how many 'fans' you have blowing on the card.