I think most of today's software runs on any AMD64 CPU. That said, this is changing. GCC and LLVM developers have introduced aliases "x86_64-v2" through "x86_64

I think most of today's software runs on any AMD64 CPU. That said, this is changing. GCC and LLVM developers have introduced aliases "x86_64-v2" through "x86_64-v4", with the non-existent "v1" being the base spec as defined by the Athlon 64/Opteron. v2 adds for example SSE4.2 and SSSE3, present since Intel Nehalem (first-generation Core i7 etc). I think other families support v2 since Intel Silvermont (Atom), AMD Bulldozer (FX), and AMD Jaguar (AMD E-series). I think one of the bigger losses would be AMD Phenom/Phenom II. I think Red Hat wants to require x86_64-v2 starting with RHEL9. Arch Linux seems to also have considered it, but seemingly has since decided to support both v1 and v3, to provide both a bigger speed boost and better compatibility with old PC's.