A thing I want to clarify. One thing is a resolution for a game, and a very different thing is a desktop resolution. Oldest 1mb cards support 1024x768x16bits. However when you are saying safest resolution for a game you should have in mind fillrate power of the machine as well. An old 8mb daytona card works nice enough at 640x480 (if you fix the clipping problem) but you kill it at 800x600.