Canonical is experimenting with x86_64 micro-architecture feature levels! They have produced an experimental build of Ubuntu Server using x86_64_v3 for requiring basically Intel and AMD CPUs with AVX capabilities. But they aren’t yet committing to it as a default or when such a change may materialize…

Source: Phoronix – Ubuntu Linux Evaluating x86-64-v3 Based Build – AVX & Newer Intel/AMD CPUs