Brent_Justice said:FP16 frame buffer blending can be added to any future ATI card as well, it is NOT a SM 3.0 feature
Its not that without looping, you have to do HDR in 5 or so passes.
With looping and branching its down to 2
This shader is multipass shader like many new shaders that are going to be used, where sm 3.0 has a distinct advantage of cutting down passes.