I HAD THE SAME problem get a small glasses screw driver and unscrew the top metal plate on the graphics card. When i did that i found a huge chunk of dust inside not able to be removed by a can of compressed air...it is stuck inside trus t me lol i had the same exact problem and the dust should be to the left of the metal heat sink inside. its a flaw in the fan engineering... attracts alot of freakin dust you will find a pretty big chunk of a dust bunny in there... its really well hidden inside the heatsink not able to be seen from the outside