AVD - CPU Usage - vCPUs

Hoping someone can explain this to me.

We have NV24sv3 VMs running.  We have noticed that if we get above 12 users on one of the VMs the overall CPU% goes between 70% - 90+% and I am not sure why.   Our scaling script has its sessionthresholdperCPU set to 1, but it seems like sessions are taking up more CPU than they should.

Also, I've noticed when logging in that all 24 logical processors on the VM will go up to 70+% while the login finishes and OneDrive loads.  Why would all 24 be doing that for my login?

Maybe I am misunderstanding sometthing, but it seems like sessions should be utilizing one of those logical processors correct?

Any help is greatly appreciated.