With another HD 6990 4GB arriving, we take the time to have a proper look at the overclocking potential of the model. It was great that we achieved 1GHz on both cores on our Sapphire sample, but considering we had to run the fan at 100% which generated in excess of 90 dB of noise, we understand that it's hardly a feasible option for most people. So instead of testing the HIS HD 6990 4GB at its reference speeds or in CrossFireX (two things we've already done), we'll instead be testing its overclocking potential with the fan set to a much more bearable AUTO. Of course, we'll again be using MSI Afterburner software to overclock and that means we'll be able to increase the core voltage on both our cores which should help us achieve a strong overclock. Before we get into that, though, let's first check out the package of the HIS card before taking a closer look at the card itself. Once we've done that we'll of course check out the specifications on the model, but more importantly the overclock we managed to achieve. Then the fun stuff begins and we find out just what kind of performance we're able to get from the card when it's overclocked above the 880MHz that AUSUM mode offers us.