[jiggawatts]

Modern CPUs like the AMD EPYC server processor are "always NUMA", even in single-socket configurations!

They have 9 chips on what is essentially a tiny, high-density motherboard. Effectively they are 8-socket server boards that fit in the palm of your hand.

The dual-socket version is effectively a 16-socket motherboard with a complex topology configured in a hierarchy.

Take a look at some "core-to-core" latency diagrams. They're quite complex because of the various paths possible: https://www.anandtech.com/show/16214/amd-zen-3-ryzen-deep-di...

Intel is not immune from this either.Their higher core-count server processors have two internal ring-bus networks, with some cores "closer" to PCIe devices or certain memory buses: https://semiaccurate.com/2017/06/15/intel-talks-skylakes-mes...