Not sure where these performance numbers are coming from. Watch the vid here.
Around the dragon in the heaven bench using DX11 a 480 is doing 43-45FPS @ 1920x1080.
My HD 5870 @ 1030|1300 will dip to 23FPS in the same scenario save @ a 1920x1200 res.
Folks need to be careful with results from this bench. Many folks will throw up results from DX10 cards with DX11 set in the bench. If your cards can't do tesso you aren't getting a DX11 result. Set 10 and contrast the FPS.
I'll probably grab one myself as I'm all about single strong GPUs.