If you use eVGA Precision or RivaTuner the sliders will tell you 713/1479/1250 but I "Think" if you look at the graphs on the left that track the actual frequencies being used they may not be the frequencies you think. Can you grab a screen shot showing the graphs? See my screenshot below from Rivatuner. I circled in red the core and shaders. (This is my wife's machine, not my rig with the GTX260 so ignore the actual numbers).