NUMA (non-uniform memory access)
Beginner
When some memory sits closer to a processor than other memory. The far memory takes longer to reach.
Novice
A design where each CPU has its own local memory and can also reach the other CPU’s memory, but more slowly. Software tries to keep data near the CPU that uses it.
Expert
Memory is partitioned into nodes with different latency and bandwidth from each core. Remote-socket accesses cross the inter-socket link; CXL memory shows up as a further, CPU-less node. Placement and page migration policies decide the performance.
Explained in Board and server (Systems).