Processor
When adding processor object, you have _Total object and 0, 1 .. which are the processor number. Following the graph for _Total (Red) , 0 (Blue), 1 (Pink) objects for % Processor Time counters. ( Colors given in the graph for relevant counter)
In the above graph, you will see _Total is NOT the total of processer 0 and 1. But it is the average of them. For example, let us say you have four processors of % Processor time of 20, 30, 50, and 80 and _Total count will be 45. i.e. (( 20 + 30 + 50 + 80 ) /4)
Process
While processor is the counter for your processors and Process is counter for each process you are executing right at the moment. For example: if you wish to measure % processor for sqlserver, this is the measure you have to select. in this also, you have the _Total counters. Unlike the Processor counter this counter is sum of all the processes INCLUDING idle processor.
Read more: Beyond Relational