Currently actually only Skylake Xeons support AVX-512, the shiniest and newest incarnation of SIMD. No desktop i3, i5 or i7 does that. No one is using MMX anym

Currently actually only Skylake Xeons support AVX-512, the shiniest and newest incarnation of SIMD. No desktop i3, i5 or i7 does that. No one is using MMX anymore, but even it is supported by all the Xeons made in last 15 years. Xeons have had SSE just as long as other Intel CPUs. So what you said is not true at all.