Mobile versions of cards are about 50% the power or lower compared to the desktop versions. I don't trust AMD/ATi anymore, I've used them since the 3000 generation and when I had Nvidia, I had less driver problems. It's why I don't suggest them. A lot of people like the 6950, especially the ones you can unlock to 6970s(not the one posted). The 560 Ti is about 10% weaker then then 6950 at stock, but I believe they are about equal when you max overclock the both of them.

Also, shitface, AMD processor cores are much weaker then nvidia, so more of them don't make them better.