Under Resources for a node you have 'CPU and Memory Utilization' and 'Pysical Memory' and 'Virtual Memory' under Volumes.
What is the difference?
CPU and Memory utilization tells Orion to collect CPU and Memory utilization stats. These are percentages. These feed the CPU Load and Memory Utilization gauges (among other resources).
Physical memory grabs the total physical memory available and virtual memory grabs the total virtual memory available; see the Disk Volumes resource.