When I placed my dual intel order, I also had the choice for an AMD X2 .. but it was more expensive, and according to the shop-wizz/tech, for audio/video the Intel won over AMD.
Are you talking about dual core or core 2 duo? The old intel dual core were nice, but AMD were miles ahead, particularly for gaming. The new core 2 duo's are entirely different though, and considerably better than AMD's dual core chips, it would seem.
I have an 830 myself. It's nice and very handy for encoding a dvd and playing a game at the same time, but not on a par with either the AMD X2's or the Intel Core 2 Duo's for gaming performance.