I have a mini Mac attached to a 640x480 projector. Sometimes I manually set the computer to a higher resolution (which the projector will display) but it often

I have a mini Mac attached to a 640x480 projector. Sometimes I manually set the computer to a higher resolution (which the projector will display) but it often sets itself back to 640x480. Also if that is the display resolution, there is no need for games to render any more pixels :)