Originally posted by Ruined
Not necessarily. Though Valve did make a mixed mode path, AFAIK there are other things Nvidia could attempt to optimize during shader compilation such as reordering instructions for their shader architecture. In the original HL2 benchmarks, the 5900 Ultra was only 20% behind the 9800PRO - based on the nature of NV3x, I see that number able to be made up with optimizations. And, as we can see from the final result of 3dmark03, Nvidia's shader replacement can look just as good as the original if they work hard enough on it, while offering very fast speeds.
*sigh*.. Valve took 5x longer to write the shaders for the FX. Which obviously included shader reorganization etc.. not just dropping a _PP behind all the little instructions.