Well, here is my card's bios if it's of any use:

Leadtek WinFast PX7950GX2.zip

Maybe by -=Merlin=- can find the fan code and add it to your bios

The fans are set at 50% for low power and performance 3D and 35% for 2D.
They are contollable in Rivatuner (both fans change speed)

If by -=Merlin=- finds some free time v_gpu=1.4v would be nice in my bios