NUMA typically affects multi-socket machines only. An exception would be high end Xeon chips since Haswell when used in a cluster-on-die configuration, but you won't find that in a desktop PC. Each socket in a multi-socket system has its own memory, and when a remote CPU accesses the memory of another CPU, it pays a fairly hefty latency penalty compared to accessing its own memory.
Just thinking about it, I guess this makes perfect sense - all memory access on a socket will converge on a common L3 cache and it would be just bizarre if somehow each core would do a 'private write-through' somehow to it's own SDRAM.
