MSI's GTX 680 Lightning is an overclocked version of Nvidia's GTX 680, intended for overclockers. To achieve interesting performance using liquid nitrogen, the GPU's voltage has to be increased. Unfortunately, Nvidia has locked the maximum voltage of the card at 1.175 volts, preventing users from burning their chips from the get-go. To bypass this security, Guru3D proposed the idea to find a software-based solution. A method was eventually found, which allowed the voltage to be increased beyond the limit using MSI's Afterburner overclocking software.
Using the bypass, the Kepler GPU reached a stable clock frequency of 1352 MHz. Guru3D found out that Nvidia is working on a new BIOS, which fixes the bypass method as well, thus limiting users to the specified maximum voltage of 1.175 V once more. The new batch of MSI GTX 680 Lightning cards will use a new BIOS and have their voltage limits updated in Afterburner 2.2.3 as well. This means that in order for the tweak to work, new GTX 680 Lightning cards will have to be flashed to the older bios.
Nvidia allegedly locked the voltages to prevent overheating GPUs and scorched PCBs, after which some consumers try and claim warranty.