The GPU fan is probably not spinning up much because most manufacturers try to keep the GPU quiet until it gets hot enough to care.
My ATI4850 didn't even break 80% RPM until 100c and only hit 100% fan speed at 107c. This was the driver default.
You can get a slot cooler and angle the fan at the GPU if you're that concerned.http://www.newegg.com/Product/Product.aspx?Item=N82E16835114024
Did you install Windows with AHCI enable and format the drive with 4KB clusters?