Benchmark Analysis and our Conclusion
It's easy to sit back and judge the 6600 GT as the overall winner in our suite of benchmarks. If we were to number the individual "victories", the 6600 GT claimed 24 wins out of a total 31, with the 9800 Pro picking up the other 7. At issue, however, is whether or not the results clearly portray the newer 6600 GT as a true "9800 killer". We're pretty confident in saying that with Doom 3, at least, there is no comparison - NVIDIA won that test hands down. The 6600 GT also held a favorable margin in the majority of other benchmarks. However, with two newer games such as Unreal Tournament 2004 and Far Cry, the 6600 GT didn't dominate. Frame rates were much closer than in the other tests, with the 9800 Pro usually excelling when AA was enabled.
By and large the 6600 GT performed very well in all of the tests we threw at it. We got some impressive frame-rates from what is essentially a mid-range card. It should also be mentioned that the ATi Radeon 9800 Pro was, at the time of its release, ATi's high-end card. Only time and new releases have pushed the price point of the 9800 Pro to under $200. Looking at the comparison from that angle lends more credibility to the NVIDIA's claims about the 6600 GT.
The combined feature set of the more powerful GeForce 6 product line, along with its value price points, should help GeForce 6600 and 6600 GT cards find a home with PC enthusiasts that want more "bang for the buck" and need an AGP version card to get it. If manufacturers market these boards smartly, touting its strengths and adding in attractive bundles, then it looks like NVIDIA will have another high volume mover on their hands this holiday buying season.