(1) I don't know if this is what they're thinking, but not all single instructions that operate on "multiple data" are vector operations... e.g. I wouldn't call summing all items in an __m128 to be a vectorized operation. Similarly I suppose not all vectorized operations are SIMD, since they might just use normal (SISD) instructions on entire arrays. But again, I'm not sure this is really what they mean; it wouldn't seem to be a very useful distinction to make.