Yup. It says that my drivers aren't supported either, but it works fine w/ my card.
Does it say this when you open RT?
"Warning! RivaTuner has not been tested with the currently isntalled display driver. It is strongly recommended etc. etc."
Just click ok, and where it says "Forceware detected" click the little arrow on the right side, then click on the icon that looks like a graphics card. Then click on the Fan tab > change the 'auto control' to 'direct control' in the dropdown box, then adjust the last slider. I have min set at 75%, idling at 40-41c, OC'd to 730/1000.