I overclocked my geforce2 gts, that i put a coper hsfan from a cpu on, and it was great, up until the hs/f fell off (why dont gfx cards use better mounts?) and then it went to hell quickly. It was fun, i mean i got maybe geforce 3 performance outa it, but think about it this way. Assume you oc your 7900 or what ever you get, and it does shorten the lifespan. At the speed of tech these days, you are going to be selling the 7900 and buying the next 8900 or what ever comes out next before you even touch the end of its life. Just keep in mind, raising voltage is scury, and heat is the enemy. Air flow is everything, unless you go to a water or phase setup.