When using a zero client to connect to your VM the session bandwidth is negotiated between the zero client and the VM. In the latest firmware  both AES-128-GCM and Salsa-256-Round12 bit encryption are selected by default. If the negotiated encryption is AES-128-GCM you should check your View Connection Server settings to see if you have PCoIP Secure Gateway selected. If you are not using the PCoIP Secure Gateway feature then edit the View Connection Server settings to uncheck this feature and allow 20Mbps session bandwidth.