I'm having the same problem with a variety of new machines that I have built.
When I RDC into the machine, the display does not update correctly. I get partial images, or refreshes only every 20-30 seconds. It is completely unusable. Eventually, it will even disconnect even though I am logged in.
From RDCing into the machine, it looks like the machine is down, but it is fine. I can connect to it with an monitor and the problem is not visible.
I think it is a problem with my network configuration.
What should I look for to resolve this?