constant high cpu usage on RDS VMs

[Comptx]

Hello, we are constantly having our staff complain about slowness and when we check, we can see the VM's cpu usage hitting 100% with really nothing going on that should cause that. our esxi 7 host specs are as follow:

Hypervisor: VMware ESXi, 7.0.3, 19193900
Model: PowerEdge R7525
Processor Type: AMD EPYC 7302 16-Core Processor
Logical Processors: 64

all of our RDS vms have similar CPU config of: CPU: 18 / Cores per socket 9

CPU
20.748 GHz used
18 CPUs allocated

any ideas on why? that cpu should be enough for anything the vm's needs.

[DSJordan]

I am seeing this in a 2019 RDS machine as well.

Non-System Idle processes add up to about 50%:

I tried hot-adding 4 more CPU, and it appears to stay roughly the same utilization with 4 more (25%) processors with,roughly, the same workload:

It happens on multiple hosts. All running VMware ESXi, 7.0.3, 20328353.

The users are using PCoIP via Horizon. The connection server and the agent are both running version 2206.