DXT5 vs 32bit clouds in DX-10

I am running the free version of DX10 that it is available here in the library and I was wondering

if DX10 has a problem with running DXT5 (compressed) clouds?

Every time I install clouds from AS2012 graphics and they are of the DXT5 format I get

untextured clouds. If I install the 32bit everything runs fine except my FPS take a dive.

Are DXT5 vs 32bit much different in terms of FPS for the sim?

How come DXT5 clouds don't render correctly if at all?

Thanks