umm, I think ur friend is just talking crap. I don't believe it requires a 6600 as a minimum. FEAR doesn't require that much, and well, FEAR is just crazy.
edit:
"Black&White 2 requires a 64MB video card with 1.1 Pixel Shader support. Supported video cards: NVIDIA GeForce4 Ti series, GeForce FX series, GeForce 6200 or greater; ATI Radeon 8500 or greater, ATI Radeon X300 or greater."
Told u!