You can overclock it nicely with stock cooling, but be careful. Put one 120mm or 2 80mm fans on it, and then you can push it a bit further, or buy an NV Silencer for it, the put another 80mm fan, and really push it! Hmm, what is it clocked at right now? They vary, so I won't assume. If it is "hot" to the touch, you are pushing it too far, or if you start to see small lines and weird shadows and colors (artifacts) on your screen, then it has gone far enough mister, LMAO!
Tell me you current clock speeds pls.