When I have a page with a few screen full of text and scroll by dragging the
vertical slider on the right, then it does scroll, but the slider lags after
the mouse. It feels like having the mouse pointer and the slider connected
with a weak spring.
It is not any particular application that shows this behaviour.
The computer is far above the required minimum with a "windows experience
index" of 4,6 and 5,9 for desktop performance.

What could be causing this?