The GeForce 8800 Ultra and GeForce 8800 GTX easily solve the task of delivering comfortable gaming conditions in every resolution, including 1920x1200. Note that there is no difference between the two cards in lower resolutions. The GeForce 8800 GTS and the GTS 320MB can be used for playing at 1600x1200 or, perhaps, even at 1920x1200 as their frame rates are never lower than 40fps. The 640MB model is 12% faster than the cheaper 320MB version in the highest of the tested resolutions.
The GeForce 8600 GTS cannot be used in resolutions above 1280x1024 unless you disable 4x MSAA. The hardware capabilities of the G84 are far inferior to those of the full-fledged G80. The GeForce 8500 GT is too slow to be used in modern games at highest graphics quality settings.