Are you sure it doesn't say: Nvidia 9800? in the requirements?TWuD
this. You really need to go to a fallout specific forum because you're going to have to tweak a few things. To help a little though... First download the latest drivers for your graphic card. Download the latest game patch too. Often they support more graphic cards in the patch. Third shut every program down that you can. Don't run virus protection, or anything that might soak up resources in the background.