Man, 80C is too high. You are slowly killing your GPU. You'd better set your graphics fan(s) to higher speed. I know it's a lot of noise, but unless you are prepared to buy a new graphics card every year, you'd better get used to it. I doubt any warranty will cover breaking of overheat.
I have this graphics card: http://www.gigabyte.com/products/pro....aspx?pid=3685
It is made so that it heats less and is cooled better, therefore it will work longer. With my old GTX260 I always had to set fan on max to keep the GPU close to 60C.