1. "CPU Ready" graph for VM has legend "CPU Ready/vCPU"
   It means it is CPU Ready per vCPU, so it is total CPU Ready for whole VM (it is sum of CPU Ready of all vCPU cores) divided by number of vCPU.
   VMWare recommends CPU Ready to be under 5%.
   
   
   
   
2. "VM CPU" graph with CPU ready
   It has legend CPU Ready/VM so it is total CPU Ready for whole VM (actually it is sum of CPU Ready of all vCPU cores).
   This graph is prepared so it looks like the same graph in vCenter vShere in new (8.) version.
   

For more details, refer CPU Ready