Disable Checksum Offloading on Network Adapter. Offload parameters, which are not compatible with the Provisioning Server network stack, could cause slow performance when enabled on the physical network adapter.
Citrix recommends disabling Checksum Offload on the network adapter of both the Provisioning Server as well as the target devices.
This setting is not applicable for Virtual Machines.
Thank David Paoleschi for this one!