what's the voltage of stock fan on Radeon?

[laugh]

I have a Radeon PCI and a Radeon AIW AGP. I am not into gaming very much. The noise from the stock fans on video cards are the loudest fan in my PCs (yeah my PCs are very quiet). I wonder if anyone knows the voltage of the fan. If they are 12v as regular case fan and CPU fan's power supply, then I can do the 7v trick to make it lot quieter.

thanks!