To FalseChristians: I agree with your experiences. I recently changed video cards of my main computer from ATI to Nvidia. I have a lot of old games I purchased at GOG.com (I have almost 80% of their games since I like DRM-free games). There were many games I could not even run decently at ATI cards under W7 64bit (I tried many settings using RadeonPro). Most notable games are Enclave, UFO series, Outcast, and Nox. For this reason I have another computer with Q9650/Gtx9800 under XP just for running old games. For instance, there are many links suggesting to set CPU affinity to one core to run Enclave under W7. I tried it using different methodology. But I was never able to run this game with ATI cards at all. There are many links about the issues to run UFO aftershock at a full screen mode. And in fact I couldn't do it either with ATI cards.
But recently after I changed my main computer's video cards from ATI to Nvidia, I was amazed to find that the new video cards can run all these problematic games without any issues under W7 64bit at all. I mean that I can run all these games with my new Nvidia cards without any efforts at all. Although I could run Dungeon Siege 1 with my old ATI cards fine, I feel that the new Nvidia cards run more smoothly than that. Surely in some games mouse lags might be problems no matter which video cards I use. But at least I can run all the games with new Nvidia cards. I wonder if Nvidia drivers might still retain codes to run old games while ATI drivers might focus on newer games mainly.
To Arkadrel: Can you show me the old link to show that ATI cards run old games better than Nvidia cards? I am interested in reading the link to see other people's experiences.