Oblivion with HDR enabled shows good performance from both the 2600 XT and 8600 GT. This is one of those titles in which the new Dx10 midrange cards really shine, as they really leave the Dx9 cards like the 7600 GT and X1650 XT in the dust, even when competing against the higher-end X1950 PRO with this title at lower resolutions.
With a minimum frame rate of over 20 fps, both cards are playable at 1280x1024 in this title, which isn't a "twitch" game and doesn't require lightening-quick reflexes.
It's worth mentioning that both the 2600 and 8600 showed a lower minimum frame rate at 1024x768 than they did at 1280x1024.
With HDR disabled and 4xAA/8xAF enabled, both cards take a solid hit. The 2600 XT's slight performance advantage disappears and the 8600 GT takes the lead again. Similar to the results in F.E.A.R., the 8600 GT is the only card that can deliver playable performance with IQ options enabled, but only at 1024x768.