How to show window contents while dragging in Windows Server 2008 R2?
Go to System (Press Windows Flag+Pause/Break) then click "Advanced system settings" on the left.
The top option should be Performance and you should be able to tick as many of the Visual Effects as you want.
If using as a Workstation, you may not want too many of them, but if using as a standard desktop, you may want the "Adjust for best appearance" selection.
(fifth one up in that picture)