x86 custom instructions

Intel is known to have created customized chips for very large clients.

This is mentioned e.g. at: www.theregister.com/2021/03/23/google_to_build_server_socs/

Intel is known to do custom-ish cuts of Xeons for big customers.

Those chips are then used only in large scale server deployments of those very large clients. Google is one of them most likely, given their penchant for Google custom hardware.

TODO better sources.