We tried to overclock our N680GTX Lightning at its default voltage of 1.175 volts and with the Power Limit set to the maximum.
The cooler worked in the automatic regulation mode. As a result, we managed to increase the base GPU clock rate by 75 MHz and the graphics memory clock rate, by 1000 MHz.
The card was stable at clock rates of 1186/1251/7008 MHz:
This is better than average, yet you can expect such results from a GeForce GTX 680. Thanks to the Twin Frozr IV cooler, the overclocked card had the same temperature and its fans rotated at the same speed as before:
After we increased the GPU voltage by 93 millivolts (the voltage would drop automatically to this value when we selected 100 millivolts), the GPU could be overclocked by 135 MHz more.
Interestingly, the memory frequency had to be reduced by 20 MHz in order to make the card stable at that GPU clock rate. So, the resulting clock rates were 1246/1311/6988 MHz:
As a matter of fact, this is the highest GPU clock rate among all five GeForce GTX 680s we have tested so far. The Twin Frozr IV must be praised again as it kept the overclocked and volt-modded GPU as cold as 71°C at a fan speed of 2070 RPM.
Our applause goes to MSI for creating such an overclocker-friendly PCB and such an efficient cooler!
We measured the power consumption of our testbed equipped with different graphics cards using a multifunctional Zalman ZM-MFC3 panel, which can report how much power a computer (without the monitor) draws from a wall outlet. There were two test modes: 2D (editing documents in Microsoft Word or web surfing) and 3D (three runs of Metro 2033: The Last Refuge benchmark in 2560x1440 resolution with maximum image quality settings).
Here are the results:
The MSI N680GTX Lightning doesn’t surprise us in terms of power consumption. Its system consumes up to 452 watts when the card works at its default frequencies and up to 500 watts when the card is overclocked. Interestingly, the system with the default AMD Radeon HD 7970 GHz Edition needs more power than the system with the overclocked and volt-modded MSI N680GTX Lightning. Each of the tested configurations is going to be satisfied with a 550 or 600-watt power supply, though. Such PSUs are commonplace in today’s gaming PCs.