http://www.ncix.com/products/index.p...ctic%20Cooling get this and ziptie a spare fan to it. Get it used if you can find one... I used spare AS5 I had lying around. A 5g tube is good for quite a few CPU/GPU applications.
That's what I did with my x1900gt and it's been quiet as a clam ever since, and happily chugging away. I want to do the same to my 4890 that I replaced it with - what a loud MOFO!