There's no problem here. 65 is fairly low. Many mainsteam cards run in the mid-to-higs 70s. You shouldn't be CPU-bottlenecked in any of those games, so the graphics card will run all-out and your temps should be around the same.
Please provide more info on how it "just cuts out." Your GPU temperature is not the issue. How are your CPU temps? On a related note, if this is a gaming build, who the heck conned you into getting an 8120?