The reason the dx8 looks good vs dx9 is they had HDR turned off. Nvidia does not support this so they turned it off for both ATI and Nvidia SS.
In the actual game with HDR in full dx9 mode the difference is suppose to be stunning.
Originally posted by aapo
You all have seen the HL2 benchmark screenshots, and there is a minimal difference between DX9 and DX8 - which tells us that DX8 shaders are at least almost as good as DX9.
If I've understood right, the only effect that can't be done properly with DX8 in HL2 is the high dynamic range light effects, because like the name says, there needs to be high range of intensity values in the shader code, which only DX9 FP numbers can offer.
I bet this is why things are generally more shiny and the water is 'brighter' in DX9 effects, there is more dynamic range available. But in the HL2 screenshot the DX8 actually looked better to me, the water was too shiny in DX9. In AquaMark3 the scenery with Radeons looked better and it had more dynamic range judging by the screenshots, IMHO, so mebbe the real DX9 is good for something after all.