AnandTech has a look at the performance PC gamers can expect see under Windows Vista with DirectX 10. Unfortunately, it isn't pretty. Despite the power of the new 10-compliant graphics cards, the choices made in developing this technology have resulted in a significant gap between what is possible and what is actually obtainable
from commercial PC hardware. What's worse, the article starts off by pointing out that much of the shiny effects exclusive to DX10 games would have been possible with DX9, had Microsoft been inclined to develop in that direction. From the article: "[Current] cards are just not powerful enough to enable widespread use of any features that reach beyond the capability of DirectX 9. Even our high-end hardware struggled to keep up in some cases, and the highest resolution we tested was 2.3 megapixels. Pushing the resolution up to 4 MP (with 30" display resolutions of 2560x1600) brings all of our cards to their knees. In short, we really need to see faster hardware before developers can start doing more impressive things with DirectX 10."