Doubt there will be much response to this with the lack of 5970's doing the rounds.
http://downloads.guru3d.com/ATI-Overvolt-Tool-for-R5970-download-2434.html
Using the ATI OverVolt Tool is rather easy as you start out with the default card voltages of 1.05V on the core and 1.10V on the memory and then you can increase it to 1.1625V on the core and 1.15V on the memory. These are just modest increases, but AMD said that it is enough to greatly increase the overclocking possibilities of the Radeon HD 5970 graphics card.
http://downloads.guru3d.com/ATI-Overvolt-Tool-for-R5970-download-2434.html