In December 2023, we announced the availability of binary Gentoo package hosting. Initially, the package set for amd64 was the base-line x86-64, compatible with any 64bit Intel or AMD machine. Now, we are excited to introduce a separate package set using the extended x86-64-v3 ISA, which provides a speed boost for compatible hardware. To check if your machine supports x86-64-v3, you can use glibc’s dynamic linker. If your hardware supports it, you can update the configuration file to download the new x86-64-v3 packages. Currently, there is no support for x86-64-v4 packages due to limited demand. It is recommended to build from source if your machine supports x86-64-v4. The recent attention towards x86-64-v3 support in Linux distros is a bit puzzling, considering the ISA is 9 years old. However, support for this instruction set was introduced late in some processor lines.
https://www.gentoo.org/news/2024/02/04/x86-64-v3.html