Minimizing Computer Screen Resolution for video games?

[akasixcon]

I have a 24" 1920x1200 native resolution monitor. When playing high-end games like Call of Duty 4 at 1920x1200, its very laggy since of my computer specs (look at my sig). The only way I can play call of duty is at a 800x600 resolution, which is stretched out to the 1920x1200 monitor; which looks really bad.

Any way to kinda "minimize" the screen so it has a 1:1 pixel aspect ratio of 800x600? Meaning I want to play the game at 800x600 but I don't want it to stretch to the 1920x1200 resolution.

It doesn't have to be just CoD4, it can be any game.

 

[carnageX]

I think there's a way to do it in nVidia Control Panel...but not for certain.

 

[KSoD]

There is no way to do that. Your drivers should be the most current ones and offer you options to change the resolution. There are ways to chagne it in games as well.