Missing Sunray filttering effect with nvidia cards.

[Esac_mirmidon]

I always had ATI cards ( from 9600 XT , X800GTO2, to X1900XT ) and one nice effect i could saw was the sunray filttering through clouds when overcast was selected.

 

Now, with my first Nvidia card ( 8800 GT 512 from Galaxy ) and 169.21 official drivers, this effect dissapears.

 

I can see the exact place of the sunray filtter ( is more white and a very thin line could be seen at the top of the overcast clouds ) but the sunshine is missing.

 

I this an issue of Nvidia cards or maybe this could be corrected with the control panel options?

 

Thanks in advance. And sorry for my poor english.