The results speak for themselves. ATI cards run pretty much faster in Halflife 2. The most unfruitful results are the numbers of NVIDIA's GeForce FX 5600 Ultra - too low for a DirectX 9 card. Even the use of the optimized codepath for NVIDIA cards (Mixed Mode) that is running with lower floating point precision and without High Dynamic Range effects shows bad results on those cards. On the other hand we must admit that NVIDIA still has plenty of time to fix issues with their drivers and increase the performance of their cards in Halflife 2, which is estimated for November this year. Since we were not allowed to test NVIDIA's Detonator 50 beta driver we can not evaluate how the performance is with this driver, which performance is way better in new DirectX 9 games, as NVIDIA says. We hope to get an explanation from Valve soon, where they explain what exact problem they have with Detonator 50.
Because of the ongoing discussions regarding "legal" or "illegal" driver optimizations, some people lost trust in NVIDIA. The new critics from Valve won't help NVIDIA to get this trust back. But it's also up to Valve now to offer a solution and a more in-depth explanation to the million owners of NVIDIA cards as to why their cards perform so badly with Halflife 2 at the moment. Of course, it's also in their interest to sell copies of the game to those people.
That is one side of the story. The other is that NVIDIA now has to prove that their cards are really ready for DX9 games - as they promise with the upcoming Detonator 50 driver in their response to Valve.