As usual I tested 3DMark05 at all resolutions with antialiasing and anisotropic filtering disabled during the primary run. On the second round I went for improved image quality turning on both 4xAA and 8xAF.
It is clear from the comparative charts that AMD (formerly ATI) has a Vista driver that maintains the same performance level as that of its Windows XP counterpart. Microsoft stated that it would not be uncommon that graphics performance under Vista would come in 5%-10% behind that running on Windows XP. Nvidia hits that target with image quality enhancements disabled but when antialiasing and anisotropic filtering are enabled it is a different story. I retested the Nvidia GeForce 7900GTX under Vista again to verify that indeed there was a 50% reduction in performance at 2048x1536 with 4xAA and 8xAF. At both 1600x1200 and 2560x1600 the performance reduction was 37%