The chaps over at TheInquirer have managed to spend some time using a Vista machine. The machine had Athlon 4000+ and 2 GB of memory with Geforce 7800 GTX card. They installed a game and they didn't have anything else than Far Cry at the moment. You can clearly see that you need more than 1GB of memory to run the game. Far Cry is not that an intensive game, and they ended up with 1.23 GB page file and you can see that they are running a single instance of Explorer and a task manager.

I have a fear of FEAR the game as it will eat significantly more than Far Cry. We FEAR that you might need even more than 2GB as FEAR of already wants 2GB memory under Windows XP. It works with 1GB as well but it works better with 2GB, and so does the Battlefield 2. We are sure that you will soon be able to buy 4GB gaming kits, at least by the end of the year when Vista gets closer.