Is it really worth overclocking a GPU? The few percent gain hardly makes a difference to general gaming. Getting an average of 38 FPS as opposed to 35FPS has no significant benefit surely, and that's what you'd gain from a 10% overclock, which is on average more than what most would get I think. (I get the feeling I'm potentially about to be proved wrong).
With a CPU the benefits of overclocking are noticeable, especially when you are talking 30-50% plus.
Playing devils advocate a little here, and hope someone can prove me wrong. Have dabbled with overclocking my GPU a little using Ntune, but as I couldn't visually see a difference I reverted back to stock settings, and just changed the cooler for a quieter option. Now less fan noise does make a difference to the gaming experience!