For starters (please refer to our announcement), and an admittedly late one since we've had a forum thread about this before due to NVIDIA's "3DMark03 optimized drivers" for their NV3x based cards recently, we have a image quality comparison between DX9's reference rasterizer and ATi's R300-based Radeon 9700PRO in 3DMark03's Game Test 4 ("Mother Nature").
The First Quick Article.
The First Quick Article.