I'm upgrading my computer too (because of RTW ). The game run perfect on my old 1,7GH CPU with new GeForce 5700 256Mb and 1GB DDR.

But I have problem with motherboard. When I install all on my new GigaByte GA-8IG1000 RTW works incorrectly (for example, there is no grass; and I think some other features of full game will be lost). This MB have chipset Intel 865G with onboard VGA. And I suspect that this onboard VGA cause problems with the game. Because everything works correctly when I install all other stuff on other MB. So I gonna change this board to another one without onboard VGA. Kagetora, I recommend you to get MB without onboard video.

About Intel and AMD. I know that Pentium works better with graphic applications (Photoshop, etc.). Therefore I think it should be better for games.