A
VPN is an extension of a private network connection over a public network (e.g. the internet).
RDP provides a graphical interface to connect to and control a Windows computer over a network. One can use RDP both locally as well as remotely via a VPN.
When using RDP locally the interface runs over the local network at up to gigabit speed, however when connecting through a VPN the speeds are dictated by the lowest connection speeds at each end, which are ususually the upload speeds.
Where I live Comcast has recently
doubled connection speeds, which (if used at both ends) will dramatically improve the RDP experience over a VPN. Scott.