GPU Boost performance and overclocking
We wanted to observe the gains given in practice by GPU Boost, which we managed to neutralise.
Moreover we managed to overclock the GeForce GTX 680 by increasing the GPU clock by 100 MHz (it therefore varies between 1106 MHz and 1210 MHz) and the memory clock by 300 MHz, which was therefore increased to 1800 MHz. The energy consumption limit was then pushed to its maximum, +32% or 224W.
Note that GPU Boost greatly complicates GPU overclocking making it difficult to test if the maximum clock imposed in certain cases is really stable. With our sample +125 MHz caused crashes in certain cases but seemed stable in others where GPU Boost wasn't pushing the GPU as high. Moreover, it imposes a voltage/clock as predefined by NVIDIA and this limits room for manoeuvre. We'll have to wait until a more evolved application allows us to force a higher voltage. In the meantime, don’t expect to be able to overclock the GPU too high.
We have also included the results of a Radeon HD 7970 at base clocks and overclocked to 1075/1650 MHz, clocks that can be attained very easily on this model.
We obtained these results at 1920x1080 at extreme and very high quality settings:
Hold the mouse over the graph to show results in fps.
Hold the mouse over the graph to show results in fps.It’s interesting to see that without GPU Boost, the GeForce GTX 680 would only have been on a par with the Radeon HD 7970.
Overclocking the GeForce GTX 680, and more particularly its memory, makes most of a difference in situations where the GTX 680 was down on its competitor. The average gain is 13%, with a peak of 18% in Alan Wake. The Radeon HD 7970 has a 15% lead with this relatively conservative overclocking, allowing it to make up some of the ground on the GeForce GTX 680.
Note that this is an average of gains and not a performance index that uses a weighting with respect to the highest performance mono-GPU card in each game and gives a result that differs by a percentage point.
