Here's an awesome overclock of the as yet unreleased NVIDIA GeForce GTX 580, taking the clock speed to almost double the stock speed.
Here's the deal. Take an NVIDIA GeForce GTX 580 and stick it into a Maximus IV Extreme motherboard kitted out with an Intel Core i7 2600K CPU. Next, rip off the huge cooler and replace it with a totally warranty-voiding liquid nitrogen cooler. Then up the core voltage to 1.5V and disable the OCP feature that controls the cards voltage draw when under load.
Then on with the overlocking! And what an overclock it is!
Take a look at these numbers that XtremeSystems forum moderator Shamino managed to achieve:
The default clock started out at 782MHz, but post-overclock hit a staggering 1519MHz, while the shader clock was boosted from 1564MHz to an amazing 3040MHz.
All this results in some awe-inducing benchmark results:
OK, hardly practical for a desktop system, but still very cool!