My Connect3D X1900XT wasn't even using the fan.
When I dumped the BIOS image I noticed the fan only reached 30% or something and didn't go up until it hit 88°C which I think is a bit late
So I ended up editing the BIOS.
Altho first I setup ATITool to change the fan speeds to see what sort of setting was best for the noise etc.
Now it only hits highs of 70°C before I think it hit 85°C or something
Before spending money on a new fan, I'd setup ATITool with some proper fan settings.