Passive cooling was rarely made with overclocking in mind, but SilentPipe 3 is one of those rare exceptions.
The cooler is divided in two compartments. The smaller one is dissipating heat inside and outside your case, while the larger one is dissipating heat only inside the case. The benefit of the large surface of this cooler is that it can cool more powerfull cards even without a fan. Thus, overclocking with this cooler won't make card noisier.
Heat is conducted from the copper base to the compartments via 4 copper heat pipes. One of the compartments is made out of copper (the smaller one), while the larger one is completely made out of aluminum.
At the time being, Gigabyte will supply this cooler with it's GV-NX76T256HI-RH Nvidia 7600GT based card with 256MB of video memory.