In SQL Server 2008, SSMS didn't separate things into NUMA nodes at all. It just presented a list of Cores, 0 to 15, one column for Processor Affinity, one for I/O Affinity. In 2012 it breaks it into 4 NUMA nodes, but I didn't know what those were, so I just carried my settings over.

So on this server, the GTA instance (for example) has its processor affinity set on three cores in NUMA Node 2, and its I/O affinity set on a core in NUMA node 3. The ENT and DOCINDEX instances both use cores in NUMA Node 4.

If there are restrictions or limitations that SQL Server has related to which cores it can use across which nodes, I would like to know what they are. I just assumed that it was a hardware construct like "sockets" that it was exposing to me, but didn't think that it made a difference when it came to assigning affinity.