You wouldn't buy an automobile based on the horsepower of the engine. Yet knowing the horsepower of the engine does give you a quick understanding of the auto. And that's the value of 3D Winbench. Yes, drivers can be tuned specifically for a benchmark. But trying to fool customers is a terrible practice and just won't work for long for any company that tries it.
Real customers run real applications.
3D Winbench is just an approximation of a whole bunch of applications. It's a good first step but by no means as good as testing a bunch of real applications. But that's the wrong question. What you should have asked is whether we have optimized our drivers to exaggerate our performance on 3D Winbench98 relative to Riva 128 performance on real 3D applications. We have certainly used 3D Winbench as one of the tools for improving our drivers.