The CPU utilization observed on the VM in Task Manager at a Guest OS level appears to not match the "CPU|Workload (%)" metric for the VM in Aria Operations.
Aria Operations 8.x
The observed discrepancy in values between the Guest OS and "CPU|Workload (%)" metric is due to the metric being a derived metric from multiple metric collections which is collected at the ESXi Host level.
The CPU Workload % shown for the VM in Aria Operations is the correct value and reflects the "CPU|Demand (MHz)" and "CPU|Total Capacity (MHz)" metric collected from the VM at a ESXi host level.
The Virtual Machine Workload (%) metric is calculated using the following formula: CPU|Workload (%) = [CPU|Demand (MHz) / CPU|Total Capacity (MHz)] * 100
For monitoring Guest OS level specific metrics we recommend using leveraging the OS and Application monitoring functionality of Aria Operations.