The difference is only relevant on a machine with more than one NUMA node. On such machines, the processors in "Processor Information" are identified by their NUMA node and their number within the node. For example, if you have two nodes with four processors each, then "Processor information" would enumerate them as
The first number of each pair is the NUMA node number. "Processor Information" also provides pseudo-instances that give node-specific totals (
1,_Total for the preceding example).
In "Processor" the processors are simply numbered serially and there is a single system-wide
_Total instance, no matter how many NUMA nodes there are.
A NUMA machine these days would normally use one of the modern point-to-point interconnects (QPI or HyperTransport) and would have more than one physical CPU socket. In these platforms, each CPU socket is its own NUMA node, with its own set of DIMM slots. Being able to easily identify CPU usage within the NUMA nodes is important in some performance tuning scenarios.