Can you be more specific and show me some screen shots and tell me exactly how I can recreate this bug?

I just fully loaded my CPU with Prime95 while RivaTuner was running and when I right clicked on any graph, I had no problem adjusting any of the parameters and saving them.

What are you using to load your CPU and what priority are you running it at?

When testing, make sure you are only using the RTCore.dll plugin and nothing else.