I recently purchased a new GPU, switching up from an HD 4870. I've always wanted to control the fan speed myself, and Rivatuner has always worked wonders. While it did work normally with my HD 4870, it doesn't now on my GTX 470. All I get is the low-level refresh settings, and low-level colour scheme settings. I noticed a previous thread about adding certain lines to the rivatuner.cfg file, but they seemed dependant on my model, so I don't know which lines would be good to try out for me. I've tested the latest version (2.24), as well as an older one (2.04), of Rivatuner.
If I let the GPU adjust the fan speed automatically, it doesn't do a very good job, and the temperature rises to 90-100 degrees Celsius when under load.