The Larrabee SIMD width will be 16 and NVIDIA's is currently 32, so that's almost the same.
Not just the rasterizer, but any application that wants to take full advantage of Larabee will have to use the SIMD vector units to the max.
Larrabee might turn out to have great performance (which I hope), but if it does, the reason will not be black magic or breaking laws of physics. The reason will be SIMD.
For some reason it's easier for me to wrap my head around one thread driving a 16-wide SIMD unit than 32 threads that execute in lockstep. I know it ends up being equivalent but it feels different.
Also, on Larrabee you can execute a different kernel on each core, while on GPUs you can't.
That's how their rasterizer works, but I'm talking about using it as a regular x86.
The way to get maximum performance out of a given chip area is to use SIMD, and that's here to stay
There's a big difference between MIMD+narrow SIMD and super wide SIMD.