I'm not familiar with Larrabee. But it looks like it's x86 plus SIMD. If so, then Intel probably has literally 1000's of man-years of validation suites for x86

I'm not familiar with Larrabee. But it looks like it's x86 plus SIMD. If so, then Intel probably has literally 1000's of man-years of validation suites for x86. If you remove some of the x86 instructions, how much of that test code do you break? The Larrabee designers probably wanted to focus on the SIMD and on putting bunches of cores onto a single die. They didn't want to reimplement (or even fuss with) the x86 part. That's not what they were interested in. Leaving x86 alone means the chip runs Windows, Linux, etc w/o any further effort. Or does it, like I said I don't know the architecture? What do you gain by breaking that? It's probably a very small part of the silicon area anyway.