I had the as well and I am using Dual 6800GTs and it wasn't the RAM. With mine it was different SLI Profiles...some games don't like them I found out. In your case I do not know why you are having that problem with an ATI card.
Ok I have installed the game and every works fine except these things:
1. I cannot change any settings that are not default except the surround sound setting.
I can not chaneg the resolution from 640x480 it always stays there... :mad:
Can anyone help me out here....I want to see this...