What did Todd mean by saying that DX11 users will get some "performance gains"? Isn't that pretty much obvious? I mean, I'd imagine a DX11 card would be better than a DX9 card, and would give better performance...
Cards that are DX11-capable can also play DX10 or DX9 mode obviously. In most cases I have seen higher frame rates for the exact same game when using DX11 mode instead of DX10 or DX9.
Tessellation is a feature of DX11 that is the one people talk about most often, because it allows more hardware processing of tessellation with rendering of higher polygon count without compromising the frame rate, and the videos that demonstrate this feature are pretty cool.
However, there are 2 other important features of DX11 that when implemented properly in a game, essentially just improve performance.
- Better Optimization for Multi-Threading – The ability to scale across multi-core CPUs will enable developers to take greater advantage of the power within multi-core CPUs. This results in faster framerates for games, while still supporting the increased visual detailing.
- DirectCompute – Developers can utilize the power of discrete graphics cards to accelerate both gaming and non-gaming applications. Basically better hardware (GPU) accelleration for gaming and video editing tasks.