A few examples to put this in perspective:
- When undocked, if I press the windows key and then begin typing "Excel," the computer will respond faster than I can type (it will guess I want Excel before I even type the letter "x"). When docked, however, there is a brief but noticeable delay when I press the windows key. Furthermore, I can type out the entire word "Excel" before the computer will actually show me the option for Excel.
- I see similar sluggishness when typing. I am typing this message on my docked Surface Pro often 1-3 characters faster than the computer actually shows the letter on-screen. When undocked, the computer is faster than my typing.
- I see similar sluggishness when selecting objects or dragging windows.
Note that task manager still shows my resources at very low percentages: 7-15% CPU; 40-58% memory; 2% disk, 0-2% network; 0-2% GPU.