The Oracle/System CPU Usage (%CPU Usage) graph on the Overview tab shows CPU utilization percentage as ~13%. This server has 8 physical CPUs which are not dual-core.
How do we interpret this graph? Does this mean the average of 8 CPUs on that server?
Referring to the graph in the screenshot, the CPU Usage is averaged between all eight processors. So, if the CPU utilization is ~13% then the breakdown would be ~1.625% per CPU.
Also, if you change the view from Baseline Range View to Resource View, you will see the breakdown between Oracle and non Oracle utilization which provides an indication of problematic areas.