Everest can output to a csv file.
Here is how to enable in RivaTuner. In the drop down menu the next to the end is the hardware monitoring box which will bring up the monitor window.
Click the setup box and it will bring up this.
If the cpu usage options are not there click the plugins box and it will bring up this window and check the cpu.dll option.
Then click ok and you should have the ability to enable the cpu usage options and you can check or uncheck what you want to log and display on the graph.
I hope this helps.