This is an interesting article comparing the GTX 460 and the 5850 in the Lost Planet 2 benchmark. It specifically covers DirectX 9 vs. DirectX 11 performance and explains tesselation and other DirectX 11 features.http://www.legitreviews.com/article/1391/1/
This pretty much sums it up:
"When it comes to DirectX 11 performance the MSI GeForce GTX 460 Cyclone 1GB video card proved to be faster than the ATI Radeon HD 5850 in Lost Planet 2."
"Once DirectX 11 was enabled the NVIDIA GeForce GTX 460 was able to run the Lost Planet 2 benchmark nearly 10% better than the ATI Radeon HD 5850. This is a rather significant come back and as you can see the NVIDIA powered MSI GeForce GTX 460 Cyclone 1GB video card does well on DX11 game titles."