Vista is pretty much just as reliable as 7 with all the updates applied. What made you decide to use the 5830 in your new system ragejg?
Also I suspect ATI will have to optimize their drivers for this game. There's a huge drop in performance DX9 -> DX11 just from using the DX11 renderer (no extra effects). Most games have an increase in performance from using the DX11 renderer. Clearly something is wrong there. This isn't much of a surprise though, when the first Lost Planet benchmark came out, it wouldn't even run on the ATI 2900 in DX10. NVIDIA slips Capcom some serious $$$