The VCPU and memory for a machine in the machine catalog is displayed in the Studio.
To increase the VCPU follow the following steps
1) On the XenDekstop controller launch the powershell
2) Load the snapins asnp citrix*
3) Run the command Get-ProvScheme “Name of Catalog to Modify VCPU”
In the image the VCPU is set to be 2.
4) Run the command
Set-ProvScheme -ProvisioningSchemeName “Name of Catalog to Modify CPU” -VMCpuCount “Number of CPU you want to add”
In the Image the VCPU has been increased to 4 from 2
5) Run the Update catalog wizard from the Citrix Studio
6) After the wizard completes the check if the VCPU has been modified or not either on the Citrix studio or using the powershell