If you ever decide to pull the cooler to change the TIM I very highly recommend putting your screw driver into a rubber band and pressing very firmly into the screw's as they strip ridiculously easy on the 4xx's. Also be sure you have the correct driver 
Ive had them out one of my 480's twice w/o issue doing that.

Ive had them out one of my 480's twice w/o issue doing that.











Forgot OC software doesnt come pre installed -_-"